returned in February 2012. In the face of objections from thousands of street protesters, parliament granted him full immunity from prosecution. Saleh's son, General Ahmed Ali Abdullah Saleh continues to exercise a strong hold on sections of the military and security forces. AQAP claimed responsibility for the February 2012 suicide attack on the presidential palace which killed 26 Republican Guards on the day that President Hadi was sworn in. AQAP was also behind the suicide bombing which killed 96 soldiers in Sana'a three months later. In September 2012, a car bomb attack in Sana'a killed 11 people, a day after a local al-Qaeda leader Said al-Shihri was reported killed in the south. By 2012, there has been a "small contingent of U.S. special-operations troops" – in addition to CIA and "unofficially acknowledged" U.S. military presence – in response to increasing terror attacks by AQAP on Yemeni citizens. Many analysts have pointed out the former Yemeni government role in cultivating terrorist activity in the country. Following the election of new president Abd Rabbuh Mansur Hadi, the Yemeni military was able to push Ansar al-Sharia back and recapture the Shabwah Governorate. Houthi takeover, Civil War and Saudi intervention In 2014, the Houthi movement, which had been waging an insurgency against the Yemeni government since 2004, began a gradual takeover of Yemen, defeating government forces in the Battle of Amran and the Battle of Sana'a (2014). Their advance continued throughout Yemen, prompting the start of the Saudi Arabian-led intervention in Yemen. The Houthis attacked Aden on 25 March 2015, beginning the Battle of Aden (2015). Despite Saudi airstrikes, the Houthis managed to take advance into the Tawahi, Khormaksar, and Crater districts. The tide turned on 14 July, when an anti-Houthi counteroffensive managed to trap the Houthis on the peninsula. By 6 August 2015, the Hadi government had captured 75% of Taiz, and the Lahij insurgency had expelled Houthis from the Lahij Governorate. Hadi fortunes dissipated on 16 August, when Houthi forces successfully counterattacked and forced the Hadi forces to retreat from Al-Salih Gardens and the Al-Dabab Mountain region. Hadi forces attributed this reverse to a lack of military equipment. In Hadramaut, Al-Qaeda in the Arabian Peninsula (AQAP) managed to take over Mukalla after winning the Battle of Mukalla (2015), and in December 2015 they took over Zinjibar and Jaar. 2016 saw the Hadi government defeat Houthi forces in the Battle of Port Midi,