Police in New York have arrested a man suspected of plotting to bomb police cars, postal offices and other targets.
Mayor Michael Bloomberg told a news conference in New York that Jose Pimentel, 27, was charged with terrorism-related offences.
Mr Pimentel was described as a "lone wolf" who also planned to target US troops returning from abroad.
He was inspired by al-Qaeda, Mr Bloomberg said.
Police Commissioner Raymond Kelly said Mr Pimentel got instructions on how to build a pipe bomb from al-Qaeda's Inspire magazine, published in the Arabian Peninsula by radical cleric Anwar al-Awlaki, who was killed by a US drone attack in September.
Mr Pimental, who had been monitored since 2009, was charged with three terrorism-related counts and two other counts, according to court documents.