The United States is pulling roughly 60% of its staff out of Cuba and warning American travellers not to visit due to "specific attacks" that have harmed US diplomats.
The US is ordering all non-essential staff in the embassy in Havana to leave, along with all family members, officials said.
Only "emergency personnel" will remain.
The US is also warning American citizens they could be harmed if they travel to Cuba.
A US State Department travel warning notes attacks on diplomats have occurred in hotels.
The officials said the US is halting visa processing in Cuba indefinitely.
They say the steps will remain until Cuba can assure the US its diplomats are safe.