The US embassy said it has received “credible reports of an imminent attack” in the Afghan capital, Kabul.
A statement on the embassy’s website on Monday urged US citizens to exercise “extreme caution” if moving around in Kabul during the next 48 hours. The statement said the embassy had no further information about the targets, timing or nature of the planned attack.
The Taliban often carry out attacks in Kabul and elsewhere, mainly targeting Afghan security forces and foreigners. Supporters of Islamic State have a growing presence in Afghanistan.
The US State Department has long warned against travel to Afghanistan. A spokeswoman said the US embassy had received the reports of a specific and credible imminent threat, which was not against the embassy, US citizens or US interests.
She would not elaborate on the nature of the threat or who was behind it, but said: “It was sufficient enough that we did feel that an email and a message should go out to US citizens in Kabul.”