NEW DELHI (AP) — India’s Supreme Court on Thursday barred Italy’s ambassador from leaving the country and demanded that he explain why his country is refusing to return two Italian marines to stand trial in the killing of two Indian fishermen, a government official said.

The court had allowed the marines to go home in February to vote in national elections with a written promise from Ambassador Daniele Mancini of Italy that they would return to stand trial. Italy announced Monday that it would not send them back.

The dispute has damaged relations between the countries, and Prime Minister Manmohan Singh of India said there would be consequences if Italy did not back down.

The Supreme Court demanded Thursday that Italy explain why it was reneging on its promise, barred Ambassador Mancini from leaving India without its permission and insisted that he file his response by Monday.