Hundreds of demonstrators gathered near the Russian consulate in the Turkish city of Istanbul on Saturday to protest the intensifying Russian and Syrian government attacks on Syria's last rebel-held province of Idlib.

The demonstrators, mostly Syrians living in Turkey, gathered close to the Russian consulate in downtown Istanbul to "show the world that Russia is complicit" in the killing of civilians in Syria's northern Idlib region, according to Mohammed Kreimesh, a protest organiser.

"We wanted to also highlight the regime's brutality against civilians and shed light on the humanitarian situation unfolding in Idlib," Kreimesh told Al Jazeera.

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Protesters in Istanbul, including women with their children, held pictures of victims of the attacks, while some brandished a banner that read: "Russia is killing our people and children and the world is not doing anything."

"What does Russia want from us? Kids, wives are dying. People are dying," Syrian demonstrator Ahmed Marwan, 24, told AFP news agency.

"We aren't terrorists, we are humans. We came to this country to live. Leaving your homeland isn't easy but we live in this pain. Enough already."

"We are here to protest this massacre going on in Syria," Turkish protester Gulden Sonmez said.

"Here I also want to make this call to Russia, and especially Bashar al-Assad ... anyone who is responsible for this massacre, all of them have to be judged and pay for these war crimes in the name of humanity," she added.

While Turkish police blocked the group from walking to the consulate, located in the busy Istiklal Street, they allowed a small number of demonstrators to unfurl a banner that read: "More than 30,000 children killed by Russia and Assad regime."

Since mid-December, Syrian government forces and their Russian allies have heightened bombardment on the southern edge of the final major opposition-held pocket of Syria.

Russia, which backs Syrian President Bashar al-Assad and Turkey, a longtime supporter of opposition factions, cosponsored a de-escalation agreement for northwest Syria earlier this year that has since faltered.

Since mid-December, Syrian government forces and their Russian allies have heightened bombardment in Idlib [Hosam Salem/Al Jazeera]

'Breaking point'

The latest violence has displaced more than 235,000 people, according to the United Nations, while many civilians have been killed despite international calls for a de-escalation.

The International Rescue Committee warned on Saturday that conditions in the region are at a "breaking point", adding that the continued violence could displace as many as 400,000 in the coming weeks.

The increase in air raids came as Syrian forces advanced on the ground. They have since December 19 seized dozens of towns and villages from armed rebels.

The advances have brought them less than four kilometres (two miles) away from Maaret al-Numan, one of Idlib's largest urban centres which sits on the M5 highway linking Damascus with the northern city of Aleppo.

The Syrian government has been battling to take control of the strategic highway, a move that would allow it to connect cities under its control and boost trade.

There are about one million Syrian refugees living near the border with Turkey, with official camps on the Syrian side already at full capacity.

Alarmed by a new wave of refugees near its border, Turkey - which hosts more than three million Syrian refugees - sent a delegation to Moscow this week in a bid to press for a fresh ceasefire deal.

Erdogan has already warned Europe that Turkey could not handle a new wave of Syrian refugees fleeing the increased bombardment in Idlib.

The war in Syria has killed hundreds of thousands of people and displaced millions since it erupted in 2011 with the repression of anti-government protests.