U.S. to investigate helicopter crashes

BAGHDAD, Iraq -- The U.S. military tried to determine Sunday whether insurgent gunfire caused the crash of two Black Hawk helicopters, killing 17 soldiers in the worst single loss of American life since the war in Iraq began.\nMeanwhile, an audio tape purportedly by Saddam Hussein urged Iraqis to escalate attacks against the occupation and "agents brought by foreign armies" -- Iraqis who support the coalition.\nThe speaker on the tape, aired on Al-Arabiya television, said the only way to end the chaos in Iraq was for Saddam and his now outlawed Baath Party to return to power.\nU.S. soldiers, meanwhile, took the offensive with the military mounting operations in Baghdad and Saddam's home region of central Iraq. The military fired a satellite-guided missile with a 500-pound warhead at a suspected guerrilla training base. Four insurgents were killed in a separate clash.\n"Any of those groups that are working against the best interest of the Iraqis are going to be targeted," said Lt. Col. William MacDonald, spokesman of the 4th Infantry Division.\nStrong explosions thundered through central Baghdad after sundown Sunday, apparently part of "Operation Iron Hammer," a new "get tough" strategy of going after insurgents before they can strike.\nLate Sunday, a large number of U.S. troops, backed by armored vehicles and helicopters, moved into the Sunni Muslim neighborhood of Azamiyah, sealing off a 20-block area and searching vehicles in a show of force.\nThe CIA said it would review the purported Saddam tape for its authenticity. But President Bush dismissed the recording.