Two suicide bombers blew themselves up at a mosque in southeastern Iran, killing at least 39 people Wednesday. A Sunni militant group called Jundallah claimed responsibility, saying the attack was a second act of revenge for the execution of the group’s leader in June. Jundallah killed 28 people last July in another mosque attack, also in revenge for the execution of their leader. Iranian officials claim Jundallah is supported by Western powers trying to “sow discord among Shiites and Sunnis,” in the words of parliamentary speaker Ali Larijani. President Obama condemned the attack.