A man who claimed he had a bomb strapped to his body walked into a Hillary Clinton campaign office in Rochester, N.H., and has taken at least one and as many as four hostages, sources say.
Democratic National Committee Chairman Howard Dean said it is "a hostage situation involving a Clinton staffer."
One federal law enforcement official told ABC News there are four possible hostages at the Clinton office, but that there was no federal involvement at this time.
Clinton was not at the New Hampshire office at the time, and canceled an appearance at the Democratic National Committee office in the Washington, D.C., area, Dean said.
ABC News' David Wright, Pierre Thomas and Jason Ryan contributed to this report.