Pakistani officials say President Asif Ali Zardari will travel to Kabul Tuesday to hold talks with his Afghan counterpart, Hamid Karzai.

Mr. Zardari's office said Monday the two leaders will discuss issues of bilateral importance and that Mr. Zardari will also offer condolences to the Afghan president on the assassination of his brother, Ahmad Wali Karzai.

Mr. Zardari's visit takes place at a time of heightened tensions between the two neighbors, following the activities of militants along their shared border.

Pakistan says militants allegedly coming from Afghan bases have killed more than 55 soldiers recently. Afghanistan accuses Pakistan of intentionally firing hundreds of rockets into its territory, killing at least 36 Afghan civilians. Both sides deny the accusations.

Meanwhile, the Pakistani Taliban has released a graphic video purportedly showing militants executing 16 Pakistani tribal police officers captured in the country's northwest last month.

The video, posted on a website, shows the officers lined up with their hands tied behind their backs. The Taliban militants, whose faces are covered, accuse the policemen of being enemies of God and of killing six children in the northwestern region of Swat Valley. The militants then open fire on the officers, killing them.

Pakistani army spokesman Major General Athar Abbas confirmed the contents of the video Monday. Abbas said the policemen were captured by militants who entered Pakistan's Upper Dir tribal region from Afghanistan's Kunar province on June 1. At least 27 security personnel and 35 militants were killed in the ensuing clashes. The Pakistani Taliban claimed responsibility for the raid.

Pakistan's government lodged a protest with Afghanistan and called on Afghan and NATO forces to crack down on insurgents on the Afghan side of the border.