(adds details) MOGADISHU, March 23 (Reuters) - A large plane burst into flames after takeoff on Friday before crashing in north Mogadishu, witnesses said. Local radio reported it had been hit by a missile. A Somali government source said the plane was a Russian-made Ilyushin carrying engineers who had been working on another damaged plane at Mogadishu airport. "I saw the plane flying at low altitude, a missile hit one of the wings, and then the plane fell," a Shabelle reporter said on air, without giving more details of the aircraft. Witnesses described seeing a plane come down, but could not confirm it had been attacked. "I saw the plane on fire...One of the wings exploded in the air...When it hit the ground, another explosion occurred," Hassan Mahamud Jama, a resident of the area, told Reuters. Columns of smoke were coming from the area on the northern outskirts of Mogadishu where the plane came down. Broadcaster Al Jazeera reported a passenger plane had been hit by a missile on takeoff, then caught fire. The Somali capital has this week witnessed the worst fighting in months as insurgents battle with government troops and their Ethiopian military allies. A spokesman for Ugandan troops in Somalia as part of an African Union (AU) peacekeeping force said he was checking the reports.