Americans at the Kabul airport should "leave immediately," the U.S. Embassy said in a security alert on Wednesday.

What they're saying: "Because of security threats outside the gates of Kabul airport, we are advising U.S. citizens to avoid traveling to the airport and to avoid airport gates at this time unless you receive individual instructions from a U.S. government representative to do so," the embassy said.

• "U.S. citizens who are at the Abbey Gate, East Gate, or North Gate now should leave immediately."
• No specific details on the threats were provided.