An Arab human rights activist was prevented from boarding a plane at Kennedy Airport while wearing a T-shirt that read, “We will not be silent,” in English and Arabic.

Raed Jarrar was at the gate to board a JetBlue Airways flight to Oakland, Calif., on Aug. 12 when four officials from the airline or a government agency stopped him and told him he could not board with the shirt on, he said Wednesday.

One official told him, “Going to an airport with a T-shirt in Arabic script is like going to a bank and wearing a T-shirt that says, ‘I’m a robber,”’ he said.

Jenny Dervin, a JetBlue spokeswoman, acknowledged the dispute and said the airline was investigating. She noted the incident came two days after British authorities announced they had foiled a plot to blow up jetliners over the Atlantic.

Though rules banning liquids and gels in carry-on baggage went into effect at U.S. airports, Dervin said there are no specific rules governing clothing.

Jarrar, who directs the Iraq project for Global Exchange, a San Francisco-based human rights organization, said he refused a suggestion from the officials that he turn his shirt inside out. In the end, officials gave Jarrar another shirt to wear over his, and he put it on rather than miss his flight.

Jarrar said he was forced to give up his seat near the front of the plane and was issued a new boarding pass for a seat in the rear.

It was unclear whether it was officials from JetBlue, the federal Transportation Security Administration or the Port Authority of New York and New Jersey, which runs the airport, who told Jarrar to remove his shirt, Dervin said.

Officials for the TSA and Port Authority said the agencies were investigating.

Jarrar, 28, is half-Iraqi and half-Palestinian and moved to the United States last year from Jordan, where he was studying. The slogan “We Will Not Be Silent” has been adopted by opponents of the war in Iraq.