Washington ? The singer formerly known as Cat Stevens is forbidden from flying into the United States because of his alleged association with possible terrorists, U.S. officials said Wednesday in explaining why a London-to-Washington flight carrying the peace advocate was diverted.

The claim was disputed by the brother of the London-born singer, who changed his name to Yusuf Islam more than 25 years ago.

David Gordon said his brother has condemned terrorist acts and donated money to terrorism victims. “He just wants to be an ambassador for peace,” said Gordon, who lives in Princeton, N.J., and serves as Islam’s business manager.

Ironically, Islam, while in Washington last May, met with officials of the White House Office of Faith-Based and Community Initiatives “to talk about philanthropic work,” according to White House spokeswoman Claire Buchan.

The office is located across Pennsylvania Avenue from the White House. Buchan said that was before Islam was added to the no-fly list.

United Airlines Flight 919 was en route Tuesday to Dulles International Airport when U.S. officials reviewing the passenger list discovered Islam was aboard. The aircraft was diverted to Maine’s Bangor International Airport, where federal agents met the plane and interviewed Islam.

He was placed on a plane back to London on Wednesday. Gordon said Islam’s 21-year-old daughter, Maymanah, was allowed to stay in the country.

Meantime, there was confusion about how someone on the “no-fly list” was allowed to board a plane. Airline personnel are supposed to check passengers’ names against people on the list. Anyone who matches is to be kept off flights.

United spokesman Jeff Green said the airline followed procedures in checking Islam’s name, and it wasn’t on the list.

“The information did not match,” Green said.

Green and Homeland Security Department spokesman Dennis Murphy said the airline and the government were working together to figure out what happened. It’s possible Islam’s name was spelled differently on the list, Homeland Security officials conceded.

Under rules imposed following the 9-11 attacks, once an international flight is bound for the United States, passenger information is forwarded to U.S. officials. The amount of data varies, but can include name, address, flight details, seat location, form of payment and meal preference.

U.S. authorities use the information to run a more thorough check against government watch lists. That’s when authorities discovered that Islam was on the plane.

The Transportation Security Administration, which is part of the Homeland Security Department, announced plans Tuesday to take over the task of checking names against watch lists before passengers get on planes. The agency is developing a computerized system that will compare passenger data with the watch lists for domestic flights only.

U.S. authorities provided few details about Islam’s alleged connection to terrorism.

One government official, who also spoke on condition of anonymity, said U.S. authorities thought donations from Islam may have ended up helping to fund blind sheik Omar Abdel-Rahman, convicted for a plot to bomb New York City landmarks, and Hamas, a Palestinian militant group considered a terrorist organization by the United States.

In July 2000, Islam was deported hours after arriving in Jerusalem. A local paper reported then that the government claimed he had delivered tens of thousands of dollars to Hamas during a visit in 1988. Islam denied ever knowingly supporting Islamic terrorists.