At least two Pakistani security troops were killed and several others injured Sunday morning in a bomb blast in Khyber tribal area, northwest of Pakistan, local sources told Xinhua.

One vehicle was also destroyed in the remote controlled bomb blast at a security checkpoint in Mamra area that occurred in Bara sub-district of the Khyber Agency bordering Afghanistan. No group has so far claimed responsibility for the bomb attack, local sources told Xinhua.

Militants have accelerated their attacks on security forces, particularly after Pakistan government had initiated a crackdown on the flood relief camps run by different disbanded militant organizations, allegedly at the behest of the United States.

Both Pakistani President Asif Ali Zardari and U.S. Senator John Kerry expressed concern over the militants run flood relief camps saying that the disbanded groups might exploit the situation in their favor. Pakistan is facing the worst floods in its history for a month that had affected over 20 million people.