The future of Mohammed Nasheed, the first democratically-elected president of the Maldives, appeared increasingly bleak on Thursday after a criminal court on the island nation issued a warrant for his arrest.

Nasheed, who has been internationally recognised for his campaigns about global warming, was ousted earlier in the week by middle-ranking officers within the Maldives' military and mutinous policemen after pitched battles between factions in the centre of the capital, Male.

The exact details of the charges against him are unclear but the 44-year-old politician has told supporters that he "expected to be in jail tomorrow".

Paul Roberts, an aide, revealed that Nasheed had been ordered to resign by a meeting of army officers at the military headquarters on Tuesday.

"He refused to resign there and then so they took him to the presidential office and he wrote a letter there. They weren't actually pointing their guns at him but they were all armed and made it very clear they were prepared to use their weapons. It was a coup d'etat," said Roberts, who is in hiding.

Ahmed Naseem, foreign minister of the Maldives and a supporter of Nasheed, made an impassioned plea for foreign intervention. "We need them to help solve the issue of this illegal government that has come to power in a coup," Naseem said.

Scores were injured, some seriously, in violence on Wednesday night when police used teargas and baton charges to break up what witnesses said were peaceful marches by the ousted premier's supporters.

Casualties included senior politicians loyal to Nasheed. At least one remains in intensive car after being beaten and kicked. Many outlying areas also reported violence with police stations attacked.

On Thursday, Male and other cities appeared calm.

Western and local governments were scrambling to gain assurances from the new president of the country, the former vice-president Mohammed Waheed Hassan, that Nasheed, who took power in 2008, would be treated well.

In the Commons, William Hague, the foreign secretary, called on "the new leadership" of the Maldives "to establish its legitimacy with its own people and with the international community".

"We hope that the new leadership will demonstrate its respect for the rule of law, including peaceful demonstrations," Hague said.

John Rankin, the British high commissioner to Sri Lanka and the Maldives, said he was concerned for Nasheed. "We are concerned that no harm comes to him. If it did, it would be a matter of serious concern for us and the international community," Rankin said.

A senior American envoy will arrive in Male on Saturday. President Mahinda Rajapaksa of Sri Lanka has telephoned the new president and asked him to ensure the safety of his predecessor.

In contrast, India's prime minister, Manmohan Singh, wrote immediately to the Maldives' new ruler to convey his "warm felicitations".

Concerns remain that the power struggle will result in fresh violence. After more than 48 hours of political turmoil, the atmosphere in Male is "very very tense", one official said.

"If they arrest [Nasheed]. I don't know what will happen if they do. God help us," said Naseem, the former foreign minister.

However, it appears likely that the ousted president's probable strategy will be to contest elections due in 2013 rather than launch a campaign on the streets.

"The ballot should decide, not battles," Nasheed told reporters outside his home in Male. He appeared confident he would win.

Nasheed won the election in 2008 with 54% of the vote. Those polls ended 30 years of rule by Mamoun Abdul Gayoom, who had been repeatedly criticised by human rights groups.

Hassan has repeatedly denied that Nasheed was forced out and has called for a government of national unity.

Officials from Nasheed's Maldivian Democratic Party said they will not join any such administration and will campaign for the return of Nasheed to power.

Senior MDP officials accuse elements within the security forces loyal to Gayoom of engineering Nasheed's removal.

This week's events were the culmination of weeks of protests after a presidential order to the military to arrest a judge accused of blocking multimillion dollar corruption cases against members of Gayoom's government.

Nasheed, educated in the UK, was detained more than 25 times during the rule of Gayoom, earning the nickname "the Mandela of the Maldives". But he struggled to contain inflation and has been criticised by Islamist groups in the Maldives, where almost all 330,000 inhabitants are Sunni Muslim.

Events appear not to have had any impact on tourists in the luxury resorts of the archipelago.