KABUL, Afghanistan — A U.S.-led coalition airstrike mistakenly hit an Afghan army checkpoint today, killing nine soldiers and wounding three, Afghan officials said.

The strike hit a checkpoint in the Sayed Kheil area of Khost province in eastern Afghanistan, said Arsallah Jamal, the province's governor.

The U.S. said its forces "may have mistakenly killed and injured" Afghan soldiers in what may have been a case of mistaken identity "on both sides."

Jamal said U.S. and Afghan troops have been conducting operations in the region for over a week, and the army checkpoint was in a fixed location. The incident killed nine soldiers and wounded three, said Gen. Mohammad Zahir Azimi, the Defense Ministry spokesman.

Apparent friendly fire incidents have happened before. In June 2007, Afghan police mistook U.S. troops on a nighttime mission for Taliban fighters and opened fire on them, prompting U.S. forces to return fire and call in attack aircraft. Seven Afghan police were killed.

In the last month, uniformed Afghan police officers have twice opened fire on U.S. troops, killing two soldiers. The police officers were killed by U.S. soldiers returning fire, but the incidents raised fears that insurgents have infiltrated Afghanistan's security forces as a cover to launch attacks.

In the country's southern Uruzgan province, a two-day battle that ended early Wednesday killed 35 Taliban fighters and three Afghan police, said Juma Gul Himat, Uruzgan's provincial police chief.