The mayor of Hoboken, N.J., met with federal prosecutors Sunday to provide information about her allegations that top aides to Gov. Chris Christie threatened to withhold Hurricane Sandy recovery money from her city if she did not approve development projects the governor favored.

The meeting is a sign of the broadening scope of the federal investigation, which began as a look into whether Christie aides engineered a four-day traffic jam in September as retaliation against the Democratic mayor of Fort Lee who did not endorse the Republican governor's reelection campaign.

A spokesman for Christie has called the Hoboken mayor's claims "outlandishly false," and both of the officials in question have denied her account.

Mayor Dawn Zimmer alleged Saturday that she was approached in May first by Lt. Gov. Kim Guadagno and then by Richard Constable, Christie’s community affairs commissioner. Each told her during in-person meetings that she needed to advance the development project to receive money she had requested to help protect Hoboken from future flooding. The city was badly damaged by flooding from the Hudson River during Hurricane Sandy.

In a statement, Zimmer said Sunday evening that she had met in the afternoon with prosecutors at the U.S. attorney's office for several hours. She said the meeting came at prosecutors' request and she provided them with documents, including a personal journal entry she said was written in May in which she described the encounters.

"As they pursue this investigation, I will provide any requested information and testify under oath about the facts of what happened when the Lieutenant Governor came to Hoboken and told me that Sandy aid would be contingent on moving forward with a private development project," she said in a statement.