A spokesman for the New York City Police Department says a terrorism task force conducted raids on several residences in the borough of Queens early Monday.
Police spokesman Paul Browne gave few details, but said the raids were the result of cooperation between the city police and federal agents.
The Federal Bureau of Investigation briefed a group of U.S. lawmakers on the events Monday. New York Representative Peter King said he was told the FBI got an emergency warrant for the raids late Sunday, after a person under surveillance for alleged links to al-Qaida visited a group of people in New York City.
One man, cab driver Akbari Amanullah, said he was told agents raided an apartment that he shares with four other Afghan men.
New York Senator Charles Schumer said he was told there was no imminent danger, and that the raids were preventative actions. He added that the incident was unrelated to President Barack Obama's visit to the city Monday.
No arrests have been reported and neither the FBI nor the New York police department would discuss the whereabouts of the al-Qaida suspect.
A White House spokesman said Mr. Obama was briefed on the investigation. The president spoke on Wall Street Monday.
New York City has been on high alert since the attacks of September 11, 2001. Last week, the city marked the eighth anniversary of the suicide hijackings that destroyed the World Trade Center that day.
Some information for this report was provided by AP and Reuters.