At least three Pakistani soldiers and four Taliban militants were killed in a clash in the Mohmand tribal region on Sunday.

Armed militants attacked a check post, triggering an exchange of fire between the two sides at Baizai area of Mohmand Agency in northwest Pakistan.

Thirteen soldiers were also injured in the clash, security sources were quoted as saying by TV news channels.

The militants used rockets to target the security forces and the troops fired artillery shells at rebel hideouts.

The clash occurred in a region near the Afghan border, where militants frequently launch attacks on security forces.

Security sources said militants had established bases in remote mountainous areas and crossed into Afghanistan in the wake of operations by troops.

Pakistan says militants have recently launched several attacks on border check posts from Afghan soil.

The Foreign Ministry summoned Afghan diplomats on two occasions to protest over recent incursions.

Security sources said militants have carried out at least four incursions into Pakistani territory from Afghan soil in less than a month.

The attacks killed nearly 40 Pakistani security personnel and civilians.

Pakistan raised the militant incursions from Afghan territory with President Hamid Karzai when he visited Islamabad during June 10-11.

Karzai promised to stop militants if it was proved that they were using Afghan soil.

Pakistani Taliban deputy chief Maulvi Faqir Muhammad said last week that he was in the northeastern Afghan province of Kunar and would attack Pakistani forces in Bajaur Agency.

Another Pakistani Taliban leader, Maulana Fazaullah, is believed to have crossed into Afghanistans Nuristan province and has regrouped his fighters there.

Fazaullah led a bloody campaign against Pakistani forces in the Swat valley during 2008-9.