WASHINGTON - For hire: more than 1,000 U.S.-trained former soldiers and police officers from Colombia. Combat-hardened, experienced in fighting insurgents and ready for duty in Iraq.

This eye-popping advertisement recently appeared on an Iraq jobs website, posted by an American entrepreneur who hopes to supply security forces for U.S. contractors in Iraq and elsewhere.

If hired, the Colombians would join a swelling population of heavily armed private military forces working in Iraq and other global hot spots. They also would join a growing corps of workers from the developing world who are seeking higher wages in dangerous jobs, what some critics say is a troubling result of efforts by the United States to ''outsource'' its operations in Iraq and other countries.

In a telephone interview from Colombia, the entrepreneur, Jeffrey Shippy, said he saw a booming global demand for his ''private army'' and a lucrative business opportunity in recruiting Colombians.

Shippy, who formerly worked for DynCorp International, a major U.S. security contractor, said the Colombians were willing to work for $2,500 to $5,000 a month, compared with perhaps $10,000 or more for Americans.

But where Shippy sees opportunity, others see trouble.

Rep. Jan Schakowsky, an Illinois Democrat, worries that U.S. government contractors are hiring thousands of impoverished former military personnel, with no public scrutiny, little accountability and large hidden costs to taxpayers.

The United States has spent more than $4 billion since 2000 on Plan Colombia, a counterterrorism and counternarcotics program that includes training and support for the Colombian police and military. In June, Congress moved toward approval of an additional $734.5 million in aid to the Andean region in 2006, most of it for Colombia.

''We're training foreign nationals . . . who then take that training and market it to private companies, who pay them three or four times as much as we're paying soldiers,'' Schakowsky said.

''American taxpayers are paying for the training of those Colombian soldiers,'' she said. ``When they leave to take more lucrative jobs, perhaps with an American military contractor . . . they take that training with them. So then we're paying to train that person's replacement. And then we're paying the bill to the private military contractors.''

An estimated 20,000 Iraqis and about 6,000 non-Iraqis work in private security in Iraq, said Doug Brooks, president of the International Peace Operations Association, a trade group representing the burgeoning industry.

Security accounts for as much as 25 percent of reconstruction costs in Iraq, eating a substantial portion of an $18.4-billion rebuilding package funded by the United States.

Fijians, Ukrainians, South Africans, Nepalese and Serbs reportedly are on the job in Iraq. Peter W. Singer of the Brookings Institution, author of a book on the private military industry, said veterans of Latin American conflicts, including Guatemalans, Salvadorans and Nicaraguans, also had turned up.

'What we've done in Iraq is assemble a true `coalition of the billing,' '' Singer said, playing off President Bush's description of the U.S.-led alliance of nations with a troop presence in Iraq as a ``coalition of the willing.''

There are no reliable figures on the number of guards from Colombia or other countries. According to Shippy, private military experts and news reports, North Carolina-based Blackwater USA has sent 120 Colombians to Iraq.

The reports are difficult to verify because many large companies, including DynCorp, which is based in Texas and operates in 40 countries, have policies against speaking to the media.

Shippy, an Air Force veteran whose work for private military contractors has included stints in Saudi Arabia, Ecuador and Iraq, extolled the Colombians' virtues.

''These forces have been fighting terrorists the last 41 years,'' he wrote in his Web posting seeking work. ``These troops have been trained by the U.S. Navy SEALs and the U.S. [Drug Enforcement Administration] to conduct counterdrug/counterterror ops in the jungles and rivers of Colombia.''

The Colombians would join the lucrative private military industry in Iraq even as the U.S.-funded war against drug traffickers continues to rage in their homeland. Experts are divided on the effect that would have on U.S. national interests. ''It's not necessarily self-defeating, but it's not optimal,'' Singer said.