Image copyright AP Image caption It is not clear where the IS militants have taken the abducted Assyrians 
 
 There are fears that more members of an Assyrian Christian community in north-eastern Syria were abducted by Islamic State militants than at first thought. 
 
 Initial reports had put the number of missing at 90, but one activist said as many as 285 people had been seized on Monday in Hassakeh province. 
 
 Efforts to try to negotiate their release are reported to be under way. 
 
 Some 1,000 local Assyrian families are believed to have fled their homes in the wake of the abductions. 
 
 Kurdish and Christian militia are battling IS in the area, amid reports of churches and homes having been set ablaze. 
 
 Thousands of Christians in Syria have been forced from their homes by the threat from IS militants. 
 
 In areas under their control, Christians have been ordered to convert to Islam, pay jizya (a religious levy), or face death. IS militants in Libya also recently beheaded 21 Egyptian Coptic Christians. 
 
 Kurdish offensive 
 
 The Assyrians were seized by the militants as they swept into 12 villages along the southern bank of the Khabur river near the town of Tal Tamr before dawn on Monday. 
 
 The Syrian Observatory for Human Rights, a UK-based activist group, said at least 90 people had been abducted, most of them women, children and the elderly. 
 
 However, the Syriac National Council of Syria put the figure as high as 150, while Afram Yakoub of the Assyrian Federation of Sweden said sources on the ground had told him that up to 285 people were missing, including 156 from the village of Tal Shamran and 90 from Tal al-Jazira. 
 
 "These were peaceful villages that had nothing to do with the battles," Nasir Haj Mahmoud, a Kurdish official in the YPG militia in north-eastern Syria, told the Reuters news agency. 
 
 There are conflicting reports as to where the families have been taken. 
 
 Kino Gabriel, a spokesman for the Syriac Military Council - a Christian militia fighting alongside the Kurdish Popular Protection Units (YPG) - told the BBC that it believed the captives had been taken to Abdul Aziz mountain. 
 
 Osama Edward of the Sweden-based Assyrian Human Rights Network told the AFP news agency that the captives had been taken to the IS stronghold of Shaddadi, as did Syria's state news agency, Sana. 
 
 Another report said they were in Raqqa, 145km (90 miles) to the west, the de facto capital of the "caliphate" declared by IS last June. 
 
 Syria's Christians 
 
 Thought to have constituted about 30% of the population as recently as the 1920s 
 
 Long part of Syria's elite - founder of ruling Baath party was a Christian 
 
 Before the war made up some 10% of Syria's 22 million people 
 
 Up to 40,000 of those were Assyrians. They speak Syriac, a form of Aramaic, the language of Christ 
 
 Hundreds of thousands have been displaced by the fighting 
 
 Some have taken up arms to defend themselves against Islamists 
 
 Syria's beleaguered Christians 
 
 The BBC's Jonny Dymond in Beirut says the motive for the seizure of so many Assyrians is not yet clear. Our correspondent says it may be that the captives are to be used as part of a swap with the Kurdish forces. 
 
 Hundreds of Assyrians who were living in villages on the north bank of the Khabur river and elsewhere are reported to have fled following the attack to the largely Kurdish-controlled provincial capital of Hassakeh, to the south-east, and Qamishli, another city to the north-east. 
 
 Image copyright AP Image caption IS has forced Christians living in its territory to either convert to Islam, pay a religious levy or face death 
 
 Mr Edward said two historic churches had been burned down in captured villages - one in Tal Hurmiz and the other in Qaber Shamiya. The Syrian Observatory also reported that a church in Tal Shamran had also been damaged. 
 
 Mr Gabriel said IS had moved a big force into the area and were trying to take control of Tal Tamr. 
 
 The Syriac Military Council had about 400 fighters in the area and at least four had been killed in clashes with the jihadists, he added. The YPG has deployed between 1,000 and 1,500 fighters. 
 
 The YPG is also continuing a major offensive launched on Sunday against IS some 100km (60 miles) to the east, near the border with Iraq - an area of vital importance to the jihadists. ||||| BEIRUT A U.S.-led alliance launched air strikes against Islamic State on Thursday in an area of northeast Syria where the militants are now estimated to have abducted at least 220 Assyrian Christians this week, a group monitoring the war reported. 
 
 The Syrian Observatory for Human Rights said the air strikes targeted Islamic State fighters near the town of Tel Tamr, where the militants, also known as ISIS, had captured 10 Assyrian villages. 
 
 A prominent Syrian Christian, Bassam Ishak, told Reuters: "Some people have tried to call them by cellphone, the relatives that have been abducted, and they get an answer from a member of ISIS who tells that they will send the head of their relative. 
 
 "They are trying to terrorize the parents, the relatives in the Christian Assyrian community," said Ishak, who is president of the Syriac National Council of Syria. 
 
 Islamic State has staged mass killings of religious minorities, as well as fellow Sunni Muslims who refuse to swear allegiance to the 'caliphate' it has declared in parts of Syria, Iraq and other areas of the Arab world. 
 
 Its fighters were shown beheading 21 Egyptian Coptic Christians in Libya last week. Last August, it killed or enslaved hundreds of Iraq's Yazidis, whom it considers devil worshippers, just over the nearby frontier in Iraq. 
 
 The militants have previously used kidnappings to trade captives for their own captured fighters. It was not clear if they planned to do the same this time. 
 
 "What is happening is a threat to our existence," said Ablahd Kourieh, an Assyrian Christian who is deputy head of a Kurdish-led defense council in northeastern Syria, speaking to Reuters from the region via Skype. He estimated the number of abducted Assyrians was even higher, at between 350 and 400. 
 
 He called on the U.S.-led alliance to mount air strikes and to arm Kurdish-led forces which are battling Islamic State in the region. He estimated that 3,000 Assyrians had fled from the villages for the main cities of Qamishli and Hasaka. 
 
 "We call for bombardment of the terrorists' positions there, and the provision of quality weapons," said Kourieh. He said there had been no contact with Islamic State, which has yet to claim the abductions. 
 
 The United States and its allies have carried out hundreds of air strikes in both Iraq and Syria since launching a campaign to "degrade and destroy" Islamic State last year. Washington on Wednesday condemned the attacks against Christians, which it said included the burning of homes and churches and abduction of women, children and the elderly. 
 
 ISLAMIC STATE "NEEDS MONEY" 
 
 The attack on the Assyrians coincided with a big offensive by Kurdish YPG fighters against Islamic State in northeast Syria, a strategically vital region because it borders territory the militants control in Iraq. 
 
 The Kurds say they have cut a main Islamic State supply line from Iraq. The Observatory says 132 Islamic State fighters have been killed in that battle, the latest of a recent string of setbacks for the group in Syria. 
 
 Rami Abdulrahman, who runs the Observatory, reported new signs of financial strain for Islamic State: it had started salvaging and selling scrap metal from bombed factories and railway lines in the eastern province of Deir al-Zor. 
 
 "They need money. Ever since the air strikes hit their oil facilities and the Turkish border has been harder to cross, they have increased taxes and looked for ways to make money," he said. 
 
 Abdulrahman said 35 Islamic State fighters had been killed in battles with the Kurdish YPG near Tel Tamr. The death toll in the YPG and allied Christian militia was 25, he said. 
 
 The abducted Assyrians are believed to have been taken into Islamic State-controlled territory in Hasaka. 
 
 IS ADVANCES NEAR DAMASCUS 
 
 While Islamic State has come under pressure in its strongholds in northeast Syria, its fighters have opened a new front hundreds of miles to the southwest near Damascus, the seat of President Bashar al-Assad's government. 
 
 The group said on social media its fighters had attacked rival insurgents east of Damascus in the Ghouta region, saying it had ambushed members of the Free Syrian Army, a name adopted by an array of mainstream rebel groups. 
 
 It said the FSA suffered casualties, and Islamic State fighters seized tanks and ammunition. The Observatory confirmed the attack but said it had targeted rival jihadist brigades. 
 
 Mainstream rebels fighting Syrian government forces and allied militia in Syria's civil war have mostly been eclipsed by jihadists, complicating a U.S. plan to train and equip Syrian opposition forces to fight Islamic State. 
 
 Units from Islamic State are staging increasing attacks in the south, mostly in the Qalamoun Mountain range that runs north-south to Damascus and also borders Lebanon. 
 
 The Lebanese army deployed along that border on Thursday and fired artillery at jihadists who move between Syria and Lebanon, a Lebanese security source said. 
 
 (Additional reporting by Dasha Afanasieva in Istanbul; Editing by Mark Trevelyan)
– ISIS militants have rounded up hundreds of Christian hostages after storming through a chain of villages along a strategic river in northeastern Syria over the past three days, activists said today. The Britain-based Syrian Observatory for Human Rights puts the number of abducted Christian Assyrians at 220, many taken from more than 11 communities in Hassakeh province. The province, which borders Turkey and Iraq, has become the latest battleground in the fight against ISIS in Syria. It is predominantly Kurdish but also has populations of Arabs and predominantly Christian Assyrians and Armenians. ISIS hasn't yet owned the abductions, and the motive isn't clear; Reuters and the BBC both speculate that the militants might be looking for a prisoner swap with Kurdish forces. "These were peaceful villages that had nothing to do with the battles," says a Kurdish official in the area. ISIS began abducting the Assyrians on Monday, when militants attacked a cluster of villages along the Khabur River, sending thousands of people fleeing to safer areas. Younan Talia, a senior official with the Assyrian Democratic Organization, says ISIS had raided 33 Assyrian villages, picking up as many as 300 people along the way. It was not possible to reconcile the numbers, and the fate of the hostages remains unclear. State-run news agency SANA and an Assyrian activist group, the Assyrian Network for Human Rights in Syria, say the group has been moved to the ISIS-controlled city of Shaddadeh, a predominantly Arab town south of the city of Hassakeh. The Observatory, however, says they're still being held in nearby Mount Abdulaziz.