(Adds air strike, civilian deaths)

KABUL, June 9 (Reuters) - A NATO soldier was killed on Saturday in combat in southern Afghanistan as the alliance launched an air strike against leaders of the country's Taliban insurgency, a NATO statement said.

The NATO-led International Security Assistance Force (ISAF) said four of its troops had also been wounded in the southern battle with enemy fighters. It gave no more details.

NATO and a U.S.-led coalition have deployed more than 50,000 troops to Afghanistan to try to defeat the Taliban, an Islamist militia that controlled the country until U.S.-led forces invaded and drove them from power in 2001.

"A precision air strike targeted several influential Taliban leaders today in Helmand province," ISAF said in a separate statement, referring to the southern province which has seen some of the heaviest fighting so far this year.

It said the air strike represented a disruption to the Taliban network in southern Afghanistan but did not say if any of the targeted leaders had been killed.

ISAF, which has drawn heavy criticism inside Afghanistan over civilian casualties from its operations, also said an Afghan man had died from injuries sustained during a crash on Friday between a taxi and an ISAF military truck in eastern Ghazni province.

Four Afghan civilians had died on the spot. A fifth died on Saturday while undergoing surgery for his injuries at an ISAF medical facility, ISAF said.

"The accident remains under investigation by military and civilian authorities," the statement said.

NATO Secretary-General Jaap de Hoop Scheffer has urged alliance members to lower civilian casualties from fighting in Afghanistan, saying such incidents could undermine the mission.

Scores of Afghans have died in air strikes by NATO and U.S.-led coalition forces, stirring angry protests by Afghans and calls for President Hamid Karzai's resignation.

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