According to U.S. officials, the two most senior al Qaeda leaders in Iraq have been killed in a joint Iraqi-U.S. operation. The U.S. military called the deaths of Abu Ayyub al-Masri and Abu Omar al-Baghdadi in a Sunday morning strike “a potentially devastating blow,” and Iraqi prime minister Nuri al-Maliki said the deaths “broke al Qaeda’s backbone.” Vice President Joe Biden appeared at the White House press briefing today to praise the Iraqi role in the operation: “”This action demonstrates the improved security, strength and capacity of Iraqi security forces,” he said. [CNN]