Baghdad ? Two leaders of the Sunni insurgent group al-Qaida in Iraq have been killed in an airstrike carried out by American troops, Iraqi and U.S. officials announced Monday.

The deaths of Abu Ayyub al-Masri, as the leader of al-Qaida in Iraq is known, and Abu Omar al-Baghdadi, the alias of the head of an umbrella group that includes al-Qaida in Iraq, should disrupt insurgent attacks inside the country, officials said. Their slayings could also provide Prime Minister Nouri al-Maliki with a decisive political boost at a critical time.

“The death of these terrorists is potentially the most significant blow to al-Qaida in Iraq since the beginning of the insurgency,” Gen. Ray Odierno, the top commander of U.S. troops in Iraq, said in a statement. “There is still work to do, but this is a significant step forward in ridding Iraq (of) terrorists.”

The Saturday night raid was carried out a few miles southwest of Tikrit, Saddam Hussein’s hometown, U.S. officials said, after a series of Iraqi-led operations led to a safe house used by the insurgent leaders. An American soldier was killed during the operation when a helicopter crashed.

Al-Masri and al-Baghdadi were killed after “engaging the security team,” the U.S. military said. Al-Maliki said their bodies were found in a ditch. “We have found a lot of documents and hand-written letters” that implicated the men, the prime minister added.

Security forces also killed al-Masri’s assistant and one of al-Baghdadi’s sons, the U.S. military said. Iraqi troops took 16 men into custody after the raid.

In Washington, Vice President Biden declared that the operation demonstrated the growing strength of the Iraqi security forces. “The Iraqis led this operation,” Biden told reporters, adding that Iraqis also gathered the intelligence that led to the targeting. “In short, the Iraqis have taken the lead.”

White House press secretary Robert Gibbs described the United States as playing a supporting role.

Al-Masri, an Egyptian, rose to the helm of the al-Qaida in Iraq organization after former leader Abu Musab al-Zarqawi was killed in a U.S. airstrike in June 2006. Al-Masri reportedly moved to Iraq after the U.S. invasion of Afghanistan to help form the Iraqi branch of the organization.

The U.S. military did not provide a real name for al-Masri, who also went by the alias Abu Hamza al-Muhajer. Officials in Washington said in 2006 that al-Masri’s real name was Yusuf al-Dardiri, The Washington Post reported.