NATO and Afghan troops are fighting insurgents to recapture a district center in a major province in Afghanistan. An alliance statement Wednesday says several militants have been killed or wounded in the operation in Ajristan district of central Ghazni province, which began Wednesday with an airstrike. NATO says in the statement that the militants, who took the area Monday, were retaliating over the arrest of a key insurgent leader by the police earlier in the week. It says the militants were armed with AK-47 rifles and rocket-propelled grenades. Afghanistan faces intensifying militancy nearly seven years after the U.S.-led invasion ousted the hard-line Islamic Taliban movement from power.