The U.S. Embassy says it has received "credible reports of an imminent attack" in the Afghan capital.

A statement on the embassy's website Monday urges U.S. citizens to exercise "extreme caution" if moving around in Kabul during the next 48 hours. The statement says the embassy has 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 the Islamic State group have a growing presence in Afghanistan.

The U.S. State Department has long warned against travel to Afghanistan, which has been mired in war for decades.