KABUL, Afghanistan — U.S. officials warned Americans in Afghanistan on Monday about "credible reports of an imminent attack" on the country's capital in the next 48 hours.
The U.S. Embassy in Kabul urged Americans "to exercise extreme caution if moving around the city ... during this period of heightened threat."
In a statement entitled "Emergency Message for U.S. Citizens," the embassy said it had "received credible reports of an imminent attack" but added there were "no further details regarding the targets, timing, or method."
However, a security source within the embassy said the attack "may involve multiple assailants and car bombs" and was "classified as credible." The source added it had "not affected the normal embassy operation."
Sediq Sediqqi, spokesman with the Afghan interior ministry, told NBC News that the report was "nothing new" and that "we do get many of them daily." He added: "We take these reports very seriously and deal with accordingly."
The warning came two days after a suicide bomber unsuccessfully targeted a senior member of Afghanistan's election commission during the morning rush hour in Kabul, Reuters reported.
This attempted assault came after a month's lull of attacks in Kabul by the Taliban, the Islamist group attempting to defeat the Western-backed Afghan government.
Citing the country's "extremely unstable" security situation, the State Department continues to advise American civilians against traveling to Afghanistan.
The country has been mired in violence for decades following successive wars, the most recent conflict coming after a U.S.-led invasion toppled the Taliban from power in 2001.
Since the withdrawal of combat troops last year, around 10,000 of the remaining 13,000 foreign troops are American, according to The Associated Press. They are there to train and advise Afghan security forces.
Last month, a U.S. warplane mistakenly bombed a charity-run hospital in the northern Afghan city of Kunduz.
This article first appeared on NBCNews.com.