Smoke was seen billowing from an area near the U.S. Embassy in Kuwait on Monday as air raid sirens sounded across Kuwait in recent hours.

No immediate details were available regarding the cause of the smoke, and authorities have yet to issue an official statement, local media reported.

Meanwhile, the embassy warned in a statement posted on social media that there is "a continuing threat of missile and unmanned aerial vehicle attacks over Kuwait," urging U.S. citizens not to approach the embassy.

"Do not come to the Embassy. Take cover in your residence on the lowest available floor and away from windows. Do not go outside," the statement said.

The embassy also urged U.S. citizens in Kuwait to shelter in place, review security plans in the event of an attack, and stay alert for potential future attacks. It added that embassy personnel are sheltering in place.