Police in New York have arrested a man they say was plotting to attack post offices, police cars and soldiers returning from serving in Iraq and Afghanistan.

New York Mayor Michael Bloomberg told reporters Sunday 27-year-old Jose Pimentel was inspired by al-Qaida, but that he was working as a “lone wolf,” and not as part of a larger conspiracy.

The city's police commissioner, Raymond Kelly, said the suspect had already begun building three pipe bombs when police arrested him Saturday afternoon.

Prosecutors said at a hearing late Sunday that Pimentel was about an hour away from completing the explosive devices.

Pimentel has been charged with conspiring to build a bomb for terrorist purposes and possessing tools to wage a campaign of violence.

Authorities said the U.S. citizen was a convert to Islam and a follower of the radical cleric Anwar al-Awlaki, who was killed earlier this year in a U.S. airstrike in Yemen.

Police said Pimentel was using a bomb-making manual called “How to Build a Bomb in the Kitchen of Your Mother” and that he had been under surveillance for more than two years before his arrest.

Authorities said Pimentel was born in the Dominican Republic and lived most of his life in New York. They also said he identified himself with terrorist organizations, and was considering changing his name to Osama Hussein to honor his “heroes,” Osama bin Laden and Saddam Hussein.