Federal authorities have been questioning all day the credibility of a tip from a previously reliable source that that Al Qaeda had planned to attack Washington or New York, putting though both cities on high alert.

But authorities have not been able to corroborate any of the information from the source.

“The threat is looking less and less credible,” the official said, adding that the entire plot as outlined by the source “doesn’t seem feasible.”

“The time frame doesn’t make sense for when these operatives would have been moving into position,” the official said. “We are going back to the original source. The president will be briefed on it again in the morning, but people are questioning the credibility of this information at this time. Something is not adding up.”