BAGHDAD -- Young, lonely and struggling to make a mark.

The U.S. military presented yesterday a profile of foreign fighters, who are blamed for about 90 percent of the suicide bombings that have claimed thousands of lives in Iraq. It was based on interrogations of 48 men captured by U.S.-led forces here in the past four months, Navy Rear Adm. Gregory Smith told reporters at a briefing inside Baghdad's fortified Green Zone.

Smith said most militants were single men in their late teens and early 20s recruited by al-Qaida in Iraq, a largely homegrown Sunni Arab militant group that the U.S. military says is led by foreigners. They typically come from large, lower-income families in which they struggle to be noticed.

"Most of these young men wanted to make an impression, but paradoxically they did not tell their families they were going off to Iraq to fight for al-Qaida out of fear of disapproval," said Smith, a U.S. military spokesman.

Smith's presentation comes at a time when the number of high-profile suicide attacks in Iraq has inched up, many of them conducted by bombers with explosives strapped to their waists.

U.S. officers stress that the number of attacks overall remains down since the military finished sending an added 28,500 troops to Iraq in June. But Smith acknowledged that a modest rise in attacks using suicide vests, including 18 in February, was troubling.

"It is a difficult target to stop, and the only effective way is to take down the networks that feed this type of terrorism," he said.

In the latest such attack, police said, a man blew himself up yesterday in front of a Kurdish political party office in the northern city of Mosul, injuring a guard and six passing civilians. Two policemen were injured by a roadside bomb on their way to the scene, police said.

Fighters also have started to wear suicide vests and blow themselves up when captured, Smith said, a tactic previously used only by senior leadership.

The interviews conducted with detainees are helping U.S. forces understand the backgrounds, motivations and recruitment of foreign fighters. Smith said most were from the Middle East and North Africa, including about 40 percent from Saudi Arabia.

More than half of the about 240 foreign fighters in U.S. custody come from Saudi Arabia, Egypt and Syria, according to figures provided separately by the military. Smaller numbers were recruited in Jordan, Sudan, Libya, Yemen, Kuwait, Tunisia, Morocco and Algeria. There also are several hundred foreign fighters in Iraqi custody.

Most described their upbringing as religious but not extremist, Smith said. Many said their fathers were harsh and often abusive. Most reported little or no previous military experience. Before they were recruited, many worked as taxi drivers, construction workers and in other low-paying jobs. Others were students.

Their recruiters preyed on their desire for recognition, acceptance and friendship, Smith said. Many told their interrogators that they were first approached at their local mosques. Others were approached at work and invited to attend discussions at the mosque.

These conversations would begin as a harmless discussion about Islam that over the weeks would shift to discussing the war against U.S.-led forces in Iraq, he said.

Once they agreed to join the fight, most of the young men were flown to Syria and then smuggled into Iraq by road, he said. The facilitators who met them in Syria often entertained them at nightclubs and bars during the months it sometimes took to get them to Iraq, Smith said.

But when they reached Iraq, those destined for suicide missions were sequestered in safe houses with a copy of the Quran and few other amenities. They complained that their Iraqi handlers looked down on foreigners, did not give them enough food and treated them harshly, Smith said.

Some spoke of their disillusionment when they learned that most of the attacks carried out by insurgents were directed against the Iraqi people rather than U.S. forces.

Alexandra Zavis writes for the Los Angeles Times.