The chief of Iran's Revolutionary Guard on Monday accused the United States, Britain and Pakistan of having links with the Sunni militants responsible for a suicide bombing that killed five senior Guard commanders and 37 others.

Iran's president said those behind Sunday's bombing are hiding across the border in Pakistan, and in a phone call with his Pakistani counterpart on Monday he demanded their arrest.

A Sunni rebel group that has waged a low-level insurgency in southeastern Iran to protest what it says is government persecution of an ethnic minority in the region claimed responsibility for the attack. The claim was posted Monday on an Islamic Web site that usually publishes al-Qaida statements. Its authenticity could not be verified.