US troops launched a blazing assault on al Qaeda in Iraq overnight, leaving 22 militants dead by daybreak.

A combined force of 10,000 US and Iraqi ground troops launched the offensive in Diyala province to curb the relentless wave of car bombings and kidnappings that has continued around Iraq despite the US troop surge and new security crackdown.

Two thousand soldiers led the charge in Baquba, 30 miles northeast of Baghdad, backed up by heavily armored Stryker and Bradley combat vehicles, attack helicopters and other air support. Baquba is the capital of Diyala province, a notorious al Qaeda stronghold.

“Task Force Lightning commenced Operation Arrowhead Ripper today in a large-scale effort to eliminate al Qaeda in Iraq terrorists operating in Baquba and its surrounding areas,” said a statement released by the US military.

General David Petraeus, commander of the multi-national force in Iraq, recently named al Qaeda public enemy number one in Iraq.

The raids in Diyala reflect the migration of al Qaeda and Sunni Arab insurgent bases away from Baghdad and Anbar province, where additional US troops have been concentrated. Anbar tribal chiefs have also recently formed an uneasy alliance with US troops to drive al Qaeda out of their province, because of the group’s murderous rampages in local communities there.

Since relocating to Diyala province, al Qaeda has conducted public executions in the Baquba main square and imposed strict Islamic law on the local population.

Diyala’s Iraqi military commander, Major General Abdul-Karim al-Rubaie, said that handcuffs, swords and electricity cables – believed to have been used as implements of torture – had been seized in the Baquba raids.

“The end state is to destroy the al Qaeda influences in this province and eliminate their threat against the people,” said Brigadier-General Mick Bednarek, a deputy commanding US general in the 25^th Infantry Division. “That is the number one, bottom-line, up-front, in-your-face, task and purpose.”

The overnight assault, one of the largest single operations since the US-led invasion in 2003, is still in its opening stages.