A man has been arrested within the past 24 hours on allegations that he planned to build and explode a bomb in New York City, the New York Times reports.

The man was planning to target government workers with the bomb, according to the Times, which says it got its information on Sunday from a person briefed on the case.

New York Mayor Michael Bloomberg will be holding a press conference at 7:30 p.m., with Police Commissioner Ray Kelly and the Manhattan District Attorney, expected to be about the arrest.

The man, whose identity was not released to the Times, had purchased bomb-making materials and began to build them, a person briefed on the matter told the Times. The source told the Times that the man had been under NYPD surveillance for about a year.

The press conference will be streamed at 7:30 ET at nyc.gov.