Gunfire broke out on Monday outside Kabul’s international airport, yet again highlighting the perils of evacuation efforts. Navy Capt. William Urban, a US military spokesman, said an unknown assailant shot at Afghan security forces at the airport's northern gate, leading Afghan, US and allied troops to retaliate. He added an Afghan soldier was killed and "several Afghans" were wounded.The shooting came as the Taliban moved to shore up their position and eliminate pockets of armed resistance to their lightning takeover. The Taliban were in position near the Panjshir valley and had retaken three districts in northern Afghanistan that fell to local militia groups last week, a spokesman said, though there were no confirmed reports of further fighting.