KABUL, Afghanistan — Afghan police mistakenly thought U.S. troops on a nighttime mission were Taliban fighters and opened fire on them, prompting U.S. forces to return fire and call in attack aircraft, killing seven Afghan police, officials said today.

U.S.-led coalition and Afghan troops, meanwhile, killed more than 24 suspected Taliban fighters during an eight-hour battle in southern Afghanistan on Monday, the coalition said.

President Hamid Karzai's spokesman labeled the shooting at a remote police checkpoint in the eastern province of Nangarhar "a tragic incident" caused by a lack of communication.

"The police forces were not aware of the coalition's operation," said spokesman Karim Rahimi. "The police checkpoint in the area thought that they were the enemy, so police opened fire on the coalition, and then the coalition thought that the enemies were firing on them, so they returned fire back."

In the southern province of Kandahar, U.S.-led coalition and Afghan troops killed more than 24 suspected Taliban fighters during an eight-hour battle in southern Afghanistan, the coalition said Tuesday.

The troops were initially ambushed by militants Monday, but retreated after several of their fighters were killed.

A force of some 30 Taliban later attacked the same coalition convoy, and Western forces called in air strikes.