BURBANK, Calif. — President Barack Obama says the threat of an imminent terrorist attack against Americans is, in his words, "significant enough that we're taking every precaution."

In his first comments on the latest security threat from al-Qaida, Obama said Tuesday that Americans should go ahead with summer travel plans abroad despite global travel warnings. But he said they should "show some common sense" and recognize that some countries are more dangerous than others.

He didn't specify which countries posed the greatest threat. He also wouldn't say whether the U.S. learned of the threat through National Security Agency Surveillance programs.

Nineteen U.S. embassies and consulates in 16 countries have been ordered closed to the public until Saturday.

Obama spoke during an interview scheduled for broadcast Tuesday on NBC's "The Tonight Show."

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