Police officials said the grenades were thrown in the town of Shabqadar near Mohmand tribal agency.

"The attackers managed to flee from the scene, however police has launched a hunt for those responsible," said Zaman Khan, a police official.

Khan added that no group claimed responsibility for the attacks, which caused panic among residents.

Mohmand is one of Pakistan’s seven semi-autonomous tribal districts near the Afghan border, rife with homegrown insurgents and foreign militants.

Despite heavy military presence on both sides of the border, cross-border movements of militants (in both ways) have been a major area of concern.

Local militants have fled ongoing military offensives since 2008, taking refuge across the border and attacking Pakistani military checkpoints and civilians from there.

The army launched Operation Zarb-i-Azb in June 2014 in a bid to wipe out militant bases in the tribal areas and so bring an end to the bloody insurgency that has cost thousands of civilian lives since 2004. —AP