Ahmed Ferhani, 26, a legal U.S. resident of Algerian descent, and Mohamed Mamdouh, a 20-year-old Moroccan-born U.S. citizen, were arrested on Wednesday immediately after purchasing weapons from an undercover agent, Police Commissioner Raymond Kelly told a press conference.

"The men told undercover officers that they hated Jews and wanted to kill them," Kelly said, adding that one of the two suspects also expressed interest in blowing up the Empire State Building, a major New York landmark.

It was not immediately known which synagogue they were targeting, Kelly said.

New York City has beefed up security in major public locations in the wake of the killing of terror mastermind Osama bin Laden by U.S. military forces in Pakistan.