Al-Qaeda has acquired sophisticated surface-to-air missiles, The Independent has learned, which were used to shoot down an Emirati fighter jet in a dangerous escalation of the civil war raging in Yemen. A French-made Mirage jet, flying in the air force of the United Arab Emirates (UAE), crashed into a mountain side just outside the southern port city of Aden on 14 March. Authorities claimed that the crash was "the result of a technical malfunction", but sources dispute this, claiming that the jet was shot down with Russian munitions. The incident raises the spectre of other jihadist branches accessing sophisticated surface-to-air missiles in Syria, Iraq and further afield. The UAE is part of a Saudi-led coalition that has carried out a year-long war against Shia Houthi rebels, primarily from the air. Also involved in the war is al-Qaeda's regional affiliate, al-Qaeda in the Arabian Peninsula (AQAP). With the bombing war dragging on, AQAP has worked assiduously and quietly to consolidate its hold in south Yemen. Two pilots flying the jet were killed in the crash and locals reported seeing Apache helicopters and the jet engaged in an attack on AQAP forces dug into a district to the west of Aden. Security sources have estimated that some 300 jihadist fighters were under attack at the time the jet came down. A source in Yemen told The Independent that the surface-to-air missile was a Russian-manufactured SA-7 or "Strela". The SA-7 is a shoulder held heat-seeking missile. It has a "kill zone" range of between 15 and 1,500 metres in altitude, suggesting that the Mirage was flying low in a strafing run on the AQAP positions when it was hit. The SA-7 has been around for several decades. The most likely source is Bulgaria which, after the breakup of the Soviet Union, sold Russian military hardware, including the SA-7, to countries all over the Middle East.