The State Department updated a travel warning for Afghanistan, setting the security threat at "critical."
"No region in Afghanistan should be considered immune from violence, and the potential exists throughout the country for hostile acts, either targeted or random, against U.S. and other Western nationals at any time," the warning read.
The State Department warning added that anti-government forces such as al-Qaida and the Taliban are active in the country.
"Afghan authorities have a limited ability to maintain order and ensure the security of Afghan citizens and foreign visitors," the warning added.
U.S. and international forces in Afghanistan aim to leave the country next year after more than 10 years of engagement. Multinational forces are preparing for a departure as Afghan forces take the lead in military operations.
In December, Jan Kubis, U.N. special envoy to Afghanistan, briefed the Security Council on gains in Afghanistan. He said there was a general lack of political development in the country, however. Development gains are at risk "because of weak and inadequate" state systems.