Update at 7 a.m. ET, Sept. 9: "It shouldn't be seen as more than it is. ... It's a tip."
That's how NPR's Dina Temple-Raston describes what counterterrorism officials and experts are saying about the news that broke last night concerning "credible" but unconfirmed intelligence regarding a possible terror plot against New York or Washington, D.C., coinciding with Sunday's 10th anniversary of the Sept. 11 attacks.
Dina spoke with Morning Edition guest host David Greene. She said she's been told the tip came "out of Pakistan" from either a trusted source there or "chatter" that's been picked up. And there was enough to it, she said, that intelligence and counterterrorism officials "think it's credible information ... they have some faith in it."
But, Dina added, "they don't think it's rock-solid."
Our original post and earlier updates - Officials See No Need For Public To Change Plans Due To Terror Threat:
Following news reports of a possible "credible but unconfirmed" terror threat, Department of Homeland Security spokesman Matt Chandler has released this statement to the news media:
"As we know from the intelligence gathered from the [Osama bin Laden] raid, [al-Qaida] has shown an interest in important dates and anniversaries, such as 9/11. In this instance, it's accurate that there is specific, credible but unconfirmed threat information.
"As we always do before important dates like the anniversary of 9/11, we will undoubtedly get more reporting in the coming days. Sometimes this reporting is credible and warrants intense focus, other times it lacks credibility and is highly unlikely to be reflective of real plots underway.
"Regardless, we take all threat reporting seriously, and we have taken, and will continue to take all steps necessary to mitigate any threats that arise. We continue to ask the American people to remain vigilant as we head into the weekend."
The Associated Press says it has been told by a "counterterrorism official" that the threat may involve New York or Washington.
Update at 9:55 p.m. ET. 'If You See Something, Say Something':
New York Mayor Michael Bloomberg and his top aides continue to talk with reporters, and they continue to stress that while security - as planned - will be increased in the city over the weekend and into next week, they do not see a need for anyone in the public to change any plans.
As always, Bloomberg said, the best thing the public can do is remember that "if you see something, say something." That is: report unattended packages and suspicious activities.
Update at 9:45 p.m. ET. 'Refuse To Be Intimidated,' Bloomberg Says:
The threat is credible, but has "not been corroborated," New York City Mayor Michael Bloomberg just told reporters. He didn't go into detail. While it is being taken seriously, he urged New Yorkers to go about their business and continue to "refuse to be intimidated."
Bloomberg added that "I plan to be on the subway tomorrow morning."
Update at 9:42 p.m. ET. Gov. Cuomo Says There's 'No Reason To Panic':
"There are reports of a terrorist threat against New York or Washington, D.C.," New York Gov. Andrew Cuomo (D) says in a statement posted on his official website. "Our state law enforcement agencies are in contact with federal and local agencies. All New Yorkers should be cautious and aware as we prepare to commemorate the 9/11 anniversary. However, there is no reason to panic or allow our spirit of freedom to be dampened as we get ready to celebrate the opening of the Ground Zero site this weekend."
Update at 9:09 p.m. ET. Mayor Bloomberg To Speak:
New York City Mayor Michael Bloomberg "will hold a briefing at 9:30 p.m. w/ NYPD Commissioner Kelly & the FBI," according to a statement posted on the mayor's official Twitter page. The briefing is due to be streamed here.
Update at 9:05 p.m. ET. 'No Need To Panic':
"Rep. Peter King, R-New York, chairman of the House Homeland Security Committee, said very specific details were made known to lawmakers about the threat. 'Many agencies are looking at this from every possible angle,' he said.
"But it is not known yet if the threat is real, he said, adding, 'I would tell people now to go about their lives. There's no need to panic.' "
Update at 8:45 p.m. ET. Threat Is Considered 'Medium:'
Intelligence and counter-terrorism sources tell NPR's Dina Temple-Raston and Rachel Martin this threat is considered "medium." Also, they say they were expecting to pick up information like this and that their response is "out of an abundance of caution."
Update at 8:30 p.m. ET: NPR's Rachel Martin and Dina Temple-Raston report they have also now been told by counterterrorism officials that the credible but unconfirmed threat involves a possible plot to strike in New York or Washington.
The White House has confirmed to NPR's Scott Horsley that the president has been briefed about this.