Sri Lanka President Maithripala Sirisena is under increasing pressure to uphold the island nation’s constitution and reconvene parliament after his decision to replace the prime minister triggered political turmoil.

Sri Lanka was plunged into the crisis on Friday when Sirisena sacked Prime Minister Ranil Wickremesinghe and swore in ex-president Mahinda Rajapaksa to replace him, breaking up a fragile coalition governing the island.

Wickremesinghe said his sacking was illegal and he maintained that he was still prime minister, leading to a standoff between his party and labor unions loyal to Sirisena.

On Sunday, Arjuna Ranatunga, petroleum minister in the ousted cabinet, tried to re-enter his office, leading to clashes in which one person was killed and two were injured.

The crisis has important ramifications in a battle for influence in south Asia between Sri Lanka’s traditional ally India and China, a country that is playing an increasing role in the region.

China, long seen as a supporter of Rajapaksa, has already congratulated him on becoming prime minister.

But India, the European Union and the United States have all urged Sirisena to abide by the constitution.

“We call on the president, in consultation with the speaker, to immediately reconvene parliament and allow the democratically elected representatives of the Sri Lankan people to fulfill their responsibilities to affirm who will lead their government,” U.S. State Department spokeswoman Heather Nauert said in a statement.

Sources in diplomatic missions said most foreign envoys had yet to send congratulatory messages to Rajapaksa as it could be interpreted as legitimizing the new government while there were still complaints his appointment was unconstitutional.

Rajapaksa was not immediately reachable for comment on Monday.