Up to 20 percent of suicide car bombers in Iraq are from Algeria (search), a sign of growing cooperation between Islamic extremists in northern Africa and like-minded Iraqis, a senior U.S. military official said Tuesday.

The American officer said terror cells in the Middle East and northern Africa were increasingly joining forces as they face crackdowns in their own countries, leading to a stepped-up flow of money and Islamic extremists to Iraq.

Forensic investigations have revealed that 20 percent of suicide car bombers in Iraq are Algerian and roughly 5 percent come from Morocco (search) and Tunisia (search), according to the officer with responsibilities in Europe and Africa. The officer spoke on condition of anonymity, preferring for reasons of protocol to let U.S. commanders in Iraq speak on the record.

The majority of foreign bombers in Iraq are believed to come from countries in the Persian Gulf, mainly Saudi Arabia and Yemen, U.S. officials say.

The officer said the numbers had increased, but gave no specific figures. He said increasing efforts on the part of Algerian, Moroccan and Libyan security services to combat local terror cells have resulted in extremists joining international operations. But he warned they would later return home.

The United States has reacted by funneling more money and troops into north and northwest Africa to train and equip armies to combat the growing threat from local terror and insurgent groups like Algeria's Salafist Group for Call and Combat (search), which is believed to have links with Usama bin Laden's Al Qaeda network and is considered a terrorist organization by the United States.

The Algerian group was accused of involvement in kidnapping 32 European tourists in the Sahara in 2003 and launching a raid into Mauritania this month that left 24 people dead.

Last week, U.S. troops from the European Command — which overseas U.S military interests in Europe and most of Africa — kicked off a two-week counterterrorism training exercise called Flintlock involving forces from Algeria, Chad, Mauritania, Mali, Niger, Senegal, Nigeria, Tunisia and Morocco.

The officer said north African Islamic militant groups were providing some cash to the insurgency in Iraq — about $200,000 so far, mostly funneled through Europe to Syria and into Iraq.

Underground European networks were providing more cash, while African networks were providing manpower — mostly unskilled militants used to drive and then detonate car bombs that have killed thousands.

Once in the country, extremists join up with the Al Qaeda -linked network of Jordanian-born Abu Musab al-Zarqawi.

Islamic militants are traveling through Turkey, into Iran and crossing into Iraq — many times through unpoliced areas along Iraq's vast border.

A handful of Islamic fighters were believed to be returning to their home countries as well — people who can plan, work communications devices and design and set off explosives, the officer said.

America's military involvement in Africa is largely aimed at preventing terrorists from establishing sanctuaries in the region's unpoliced deserts and jungles, particularly those where Muslims are a majority.

Many local insurgent or terror groups are self-funded, he said, financing themselves via petty crime and smuggling operations. The Sahara desert's remote trade routes have long been believed a haven for human and drug traffickers.

The officer said there were no known permanent training camps in Africa. Instead, terror networks are now looking for "training opportunities" like the 1990s war zones in Bosnia, Chechnya and Afghanistan, and Iraq today.

U.S. military involvement in Africa will soon be the largest it has been in decades, at least financially.

EUCOM pushed to expand an initial $6 million program that covered Chad, Mauritania, Niger and Mali to Algeria, Tunisia, Morocco, Nigeria and Senegal. Now called the Trans-Sahara Counter-Terrorism Initiative (search), it is to be funded with $100 million a year for five years.