The UK Foreign Office has issued an update to its advice on Sri Lanka after the political and economic situation worsened.
A new curfew has been imposed after one person died and over 80 were injured in protests.
President Gotabaya Rajapaksa left the country on Wednesday but has not officially complied with demands by protestors to resign.
Instead, he has appointed Prime Minister as Acting President, with full executive powers, a move that was rejected protesters.
The FCDO said: “A State of Emergency has been declared and an island wide curfew imposed from 12pm on 14 July until 5am on 15 July.
“You should remain in your residence or hotel and not travel at this time.
“Those with a flight ticket will be able to travel to the airport.”
Last week, the FCDO reinstated its advice against all but essential travel to Sri Lanka.