TEHERAN: Iran's elite Revolutionary Guards promised a "crushing" response to an attack that killed several senior commanders, state television said yesterday, as the death toll from the deadliest such incident in years rose to 42.

Stepping up accusations of Western backing for those behind Sunday's suicide bombing in volatile southeastern Iran, one of the Guards' most high-ranking officers said the United States and Britain trained "terrorists" in neighboring countries.

The attack and allegations of foreign involvement risk overshadowing talks between Iranian and Western officials in Vienna later yesterday intended to help resolve a standoff with the West about Iran's nuclear ambitions.