KABUL: Afghan President Hamid Karzai held talks with his Pakistani counterpart, Asif Ali Zardari, on Tuesday amid heightened tension between the neighbours and as some Afghan lawmakers raised fears that Pakistan's spy agency was behind recent assassinations.

Gunmen killed a top adviser to Karzai and a member of the Afghan parliament in Kabul on Sunday in an attack claimed by the Taliban, but some lawmakers accused the Pakistan military's Inter-Services Intelligence (ISI) spy agency of being involved.

A senior Pakistani security official in Islamabad said the allegations were “a figment of someone's sick mind”.

The two leaders spoke about the economic and security situation faced by the neighbours and agreed that they should not let anyone disrupt security in either country, Karzai's palace said in a statement.

Zardari also offered his condolences to Karzai on the death of his brother, Ahmad Wali Karzai, a powerful and controversial leader in southern Afghanistan who was assassinated by a senior bodyguard in his Kandahar home last week.