Iran vowed revenge Friday on neighboring Afghanistan, and demonstrators demanded a holy war against its Taliban rulers, who have admitted their troops killed nine Iranian diplomats.

"I offer condolences to the martyrs' families and promise them that we will get revenge for their blood," former Iranian President Hashemi Rafsanjani, still a key official, said during prayers at Tehran University.Afterward, hundreds of worshippers staging a demonstration for a holy war against Afghanistan's rulers shouted "Death to the Taliban! Shame on Pakistan!" according to the Islamic Republic News Agency. Pakistan is seen as a major backer of the Taliban.

Relations between Iran and Afghanistan have been crumbling for weeks while Iran, through diplomacy and a show of military force, has pressed the Taliban about the fate of 11 missing Iranians. The group vanished Aug. 8 during a battle in which the Taliban, which controls most of Afghanistan, seized the northern city of Mazar-e-Sharif.

In a letter from supreme leader Mullah Omar to U.N. Secretary-General Kofi Annan, the Taliban admitted Thursday that nine Iranians had been killed by the religious army's troops. Omar said "unidentified soldiers" acting on their own killed the diplomats.

Iran's deputy foreign minister, Mohsen Aminzadeh, said Friday that the other two had escaped from their captors, Iranian television reported. He said one of them was injured but gave no details.