Tal Afar, Iraq ? Insurgents staged a classic guerrilla retreat from Tal Afar on Sunday, melting into the countryside through a network of tunnels to escape an Iraqi-U.S. force that reported killing about 150 rebels while storming the militant bastion.

With the city swept clear of extremists for the second time in a year, Iraqi and U.S. military leaders vowed to redouble efforts to crush insurgents operating all along the Syrian frontier and in the Euphrates River valley.

“Tal Afar is just one piece of an overarching operation. We are not going to tolerate a safe haven anywhere in Iraq,” said Army Maj. Gen. Rick Lynch, deputy chief of staff for coalition forces in Iraq.

As Baghdad kept a border crossing into Syria closed about 60 miles west of Tal Afar, Defense Minister Sadoun al-Dulaimi issued a warning: “The Syrians have to stop sending destruction to Iraq. We know the terrorists have no other gateway into Iraq but Syria.”

The United States and Iraq routinely charge that Syria’s government does little to stop the flow of Arab fighters across the border. Syrian leaders contend they are doing all they can.

While insurgents were retreating from Tal Afar, militants elsewhere killed one U.S. soldier and a British soldier in separate roadside bombings Sunday and assassinated an official in Iraq’s Interior Ministry.

A Task Force Liberty soldier was killed and two were wounded during a pre-dawn patrol near Samarra, 60 miles north of the capital. At least 1,897 U.S. personnel have died since the Iraq war started in March 2003, according to an Associated Press count.

In the southern city of Basra, a British soldier was killed and three were wounded in an attack on their convoy, the British Ministry of Defense said in London. Britain has reported at least 96 deaths.

Police said Maj. Gen. Adnan Abdul Rihman, the Interior Ministry’s director of police training, was fatally shot in front of his west Baghdad home as he waited for a ride to work.

Tal Afar had been cleared of militants a year ago, but insurgents moved back after U.S. troop numbers in the area were reduced.

By Sunday night, the joint force reported 156 insurgents killed and 246 captured. It said troops found a big bomb factory, 18 weapons caches and the network of escape tunnels beneath Tal Afar’s ancient Sarai neighborhood.

Most of Tal Afar’s residents fled before the fighting, and tens of thousands are living in tent cities to the north and east. Food, water and medical supplies are scarce.