Pakistani officials say hundreds of militants from Afghanistan have attacked several Pakistani checkpoints on the Afghan border, killing at least 12 people.

Officials say the Saturday fighting included casualties on the militant side, but officials did not say how many.

Authorities say the attacks began in Arando village in Pakistan's northwestern district of Chitral, near Afghanistan's Nuristan province. Militants then attacked more areas near the border.

Cross-border raids have raised tensions between Pakistan and Afghanistan in recent months as they battle protracted insurgencies by Taliban and al-Qaida-linked insurgents.

Washington has increased pressure on Pakistan to take more decisive steps against militants since U.S. Navy Seals found and killed al-Qaida leader Osama bin Laden in the Pakistani town of Abbottabad in May.