<p> A military airplane crashed while landing at the airport in the northern Mali city of Gao on Tuesday, two witnesses said.</p>.<p>"It's a Malian military airplane. Access to the airport is prohibited," said a source at the airport, who asked to remain unnamed.</p>.<p>Casualties were not yet known. Authorities could not be reached for comment.</p>.<p>Gao is home to one of the main military bases in northern Mali from which troops are battling an Islamist insurgency with the help of hired Russian fighters.</p>
<p> A military airplane crashed while landing at the airport in the northern Mali city of Gao on Tuesday, two witnesses said.</p>.<p>"It's a Malian military airplane. Access to the airport is prohibited," said a source at the airport, who asked to remain unnamed.</p>.<p>Casualties were not yet known. Authorities could not be reached for comment.</p>.<p>Gao is home to one of the main military bases in northern Mali from which troops are battling an Islamist insurgency with the help of hired Russian fighters.</p>