Student visas are a dangerous back door for potential criminals and terrorists, Sen. Chuck Schumer warned Sunday.
He and four other U.S. senators called for a federal crackdown on what they say are sham colleges handing out student visas.
"These sham universities are nothing more than a back door for foreigners -- and potentially for terrorists -- to illegally enter the United States and they must be shut down immediately," Schumer said.
Sens. Diane Feinstein of California, Claire McCaskill of Missouri, Jon Tester of Montana and Bill Nelson of Florida joined Schumer in blasting such colleges as fronts for people who pay to illegally enter the United States.
Schumer said the U.S. Immigration and Customs Enforcement Agency has already shut down three sham universities in New York since 2006 and is on the verge of closing more.
The Democratic senators are calling on the U.S. Citizenship and Immigration Services and Homeland Security to share information that could help identify the fake colleges.
The senators note several of the Sept. 11 terrorists entered the United States on student visas. They also cite recent incidents in California and in Florida where schools have been accused of being involved in the illegal visa scheme.
"Sham universities are not real institutions of higher learning, but rather operate solely for the purpose of manipulating immigration law to admit foreign nationals into the country,'' the senators wrote in a letter released Sunday.
"When the student visa program can be manipulated by bad actors, it threatens the viability of the entire program for the large majority of bona fide participants.''
The senators will ask the federal departments to determine "high-risk factors'' within 90 days and conduct site visits at schools that show such factors through data -- or the lack of data -- that legitimate schools must provide to the federal government.
The senators also seek stiffer penalties for `"sham universities'' that engage in student visa fraud.
There was no immediate comment from the federal departments.