Attackers shot and killed the head of a state-run teacher's institute who ignored warnings from militants to stop working for Iraqi authorities, police said Saturday, while the U.S. military raised the toll from clashes in the volatile Sunni city of Fallujah (search) to 20 insurgents.

Two mortars exploded early Saturday in a garden in northern Baghdad's Shalchia suburb, wounding two sleeping children, including a 13-year-old girl, hospital official Dr. Taleb Mustafa told Associated Press Television News.

The continuing violence followed U.S. Secretary of State Colin Powell's unannounced visit to Baghdad on Friday, when he said Washington will speed delivery of billions of dollars in reconstruction aid to Iraq. NATO countries agreed Friday to send a 40-member team to Iraq as soon as possible to begin training local security forces in a bid to curb the insurgency.

Assailants killed Ismail al-Kilabi, the head of the Mahmoudiyah Teachers Institute (search), 20 miles south of Baghdad, as he left a mosque following an evening prayer service Friday, police Lt. Ala'a Hussein told The Associated Press.

Hussein said militants had warned al-Kilabi to stop working for his state-run institute following the transfer of power from the U.S.-led coalition to Iraq's interim government.

During their 15-month insurgency, Iraqi militants have been targeting Iraqi police, government officials and tribal leaders in a bid to destabilize the country following the U.S.-led coalition's ousting of former President Saddam Hussein.

The U.S. military said Saturday that 20 Iraqi fighters were killed in fierce fighting between Marines, backed by Iraqi security forces, and insurgents between 7:30 p.m. Thursday and 1 a.m. Friday. A doctor from a hospital in Fallujah had earlier said 13 Iraqis were killed and 14 wounded.

Many of those wounded, including at least one child, appeared to be civilians injured in the U.S. airstrikes, hospital officials said.

The military said the insurgents started the fighting by ambushing a patrol with gunfire, mortars and rocket propelled grenades. After the Marines responded with tank and artillery fire, the insurgents fled into buildings, which the Marines targeted with airstrikes and artillery, the military said, adding that U.S. and Iraqi security forces suffered no casualties.

Iraq has been beset by surging violence in recent weeks, including a wave of kidnappings and Thursday's devastating Baqouba car bombing that killed at least 70 people.

Iraqi interim President Ghazi al-Yawer (search) said the violence proved insurgents were growing desperate.

"The bad guys, the enemy, the army of the darkness is getting more helpless and hopeless, that is why they are stepping up these things. Time and the place is on our side," al-Yawer said Friday after meeting Powell, the highest-ranking U.S. official to visit since last month's handover of sovereignty.

During his brief trip, Powell said Washington would speed up the slow pace of reconstruction funds to rebuild Iraqi infrastructure and create jobs, which will reduce support for the insurgency.

Of the NATO deployment, NATO Secretary-General Jaap de Hoop Scheffer said the 40-member team would leave for Iraq soon to begin training and report back in September about proposed relations with the U.S.-led multinational force.

"It's a distinct NATO mission," de Hoop Scheffer told reporters. "The multinational force will give protection" and "there should be a relationship between the training mission and multinational force in Iraq."

Also, a deadline set by militants to save the life of a captive truck driver expired without any word of his fate. The militants, who are holding seven foreign hostages from India, Kenya and Egypt, threatened to kill one of the men Friday evening if its demands, including a pullout by their company, were not met.

The drivers' company, Kuwait and Gulf Link Transport Co., said Friday it was sending an official to Iraq to work with Sheik Hisham al-Duleimi, head of an organization of Iraqi tribal leaders trying to negotiate the hostages' release.

Al-Duleimi told The Associated Press on Friday that he has been negotiating with Egyptian and Indian officials regarding the captives, but had not yet spoken to the kidnappers.

"I appeal to the kidnappers to be patient and to refrain from beheading one of the hostages and to extend the deadline until positive results can be reached," he said.

In Jordan, relatives of four Jordanian truck drivers held by a different group joined with fellow drivers in chanting "Death to America" during a protest march they said the kidnappers had demanded they hold as a condition for the hostages' release.