KABUL — Insurgents fired rockets into an American base in Afghanistan and damaged the parked plane of the visiting chairman of the US joint chiefs of staff, the US-led military coalition said Tuesday. The general was safe in his quarters at the time but had to take another aircraft out of the country. The rocket strike that hit the C-17 military transport plane of US Army Gen. Martin Dempsey was yet another propaganda coup for the Taliban after they claimed to have shot down a US helicopter last week. It also followed a string of disturbing killings of US military trainers by their Afghan partners or militants dressed in Afghan uniform. Such attacks killed 10 Americans in the last two weeks alone. Taliban spokesman Zabiullah Mujahid claimed responsibility for the attack, which took place late Monday night at the Bagram Air Field outside Kabul, saying Dempsey's plane was targeted by insurgents “using exact information” about where it would be. Two maintenance workers were slightly injured by shrapnel from the two rockets fired into, coalition spokesman Jamie Graybeal said. Dempsey “was nowhere near” the plane when the rockets hit near where the aircraft was parked, the spokesman added. Dempsey finished his mission in Afghanistan and had left by Tuesday morning on a different plane, said Graybeal. A helicopter on the base was also damaged in the attack, according to NATO. “Because there was some damage to the exterior of the aircraft, Gen. Dempsey left Afghanistan on a different C-17,” Pentagon spokeswoman Maj. Cathy Wilkinson. Graybeal cast doubt on the idea that Dempsey's plane may have been hit by any precision attack. Dempsey was in Afghanistan to discuss the state of the war after a particularly deadly few weeks for Americans in the more than 10-year-old war as international forces begin drawing down. He and the chief of US Central Command, Marine Gen. James R. Mattis, met with NATO and US Afghan commander Gen. John Allen in Kabul and also with a number of senior Afghan and coalition leaders. Among the topics was the escalating number of “insider attacks” in which Afghan police or soldiers or militants dressed in Afghan uniform turn their guns on coalition military trainers. An Afghan district police chief has been fired after one of his men killed a NATO soldier, marking the start of a crackdown on the increasing number of insider attacks, officials said Tuesday. There have been 32 such attacks so far this year, up from 21 for all of 2011, according to NATO. The police chief was sacked over the latest incident when a member of the Afghan national police opened fire on his foreign colleagues in the police headquarters of Spin Boldak district on Sunday, killing one and wounding another. — Agencies