The U.S. and British embassies have suspended operations in the capital of Azerbaijan.
This, after the government said it had thwarted plans from an Islamic group to carry out what was described as a "large-scale horrifying terror attack" against diplomatic missions and government buildings.
The country's National Security Ministry says one suspect was killed and several others were detained in a weekend sweep outside the capital.
The ministry says the Islamic group included an army lieutenant who stole hand grenades, assault rifles, a machine gun and ammunition from his military unit.
The U.S. Embassy sent an announcement to American citizens saying it had closed the consular office for an indefinite period because of a security threat. It says Americans should "maintain a high level of vigilance."