Maldives President Abdulla Yameen on Monday declared a state of emergency for 15 days and security forces stormed the Supreme Court in signs that a crisis over a jailed former president is coming to a head.

Yameen has run the Maldives, an island nation in the Indian Ocean, with an iron hand since 2013. But he faces mounting pressure at home and from the United States and India to release former President Mohamed Nasheed from a 13-year jail sentence and free eight other opponents from prison.

The emergency comes after Yameen earlier defied the court's ruling to free the opposition leaders.

"The President has been compelled to declare a state of emergency, due to the risk currently posed to national security," said a statement from the president's office. "Implementation of the Supreme Court ruling is — in its current form — incompatible with maintenance of public safety."

A number of countries, including China, the United States and India — issued travel advisories for the Maldives, a nation of 400,000 people best known as a beach paradise for tourists.