At least thirty five people have died and more than 250 wounded after an horrific attack on a Shi'ite religious procession in Lahore, Pakistan.

Three bombs were detonated, two by suicide bombers, as thousands of Shi'ites took part in the street procession which was marking the martyrdom of caliph Ali, the son-in-law of the Prophet Muhammad.

An initial bomb caused widespread panic after which two suicide bombers in different sections of the procession detonated bombs. The triple bombs were all detonated within a matter of minutes.

Marchers then turned on the Pakistani police claiming they had failed to provide security.

A police station and police motor vehicles were set alight.

Pakistan's President Asif Ali Zardari condemned the bombings as "a cowardly act of terrorism," and said justice would be dealt to the perpetrators. Prime Minister Yousuf Raza Gilani said terrorists were striking while the country was dealing with floods that have devastated Pakistan.

VOA News reported in another development, that Pakistan's military launched air raids on Tuesday and Wednesday on suspected militant hideouts in the northwestern tribal region of Khyber. Authorities said the strikes killed at least sixty people, including some women and children.

Officials accused the militants of using relatives as human shields. Khyber is a key route for U.S. and NATO convoys carrying supplies to coalition troops in neighboring Afghanistan.