The former president of the luxury resort islands of the Maldives faced arrest on Thursday after being ousted from his post earlier in the week in what he said was a coup at gunpoint.

A criminal court in the capital Male issued arrest warrants for ex-president Mohamed Nasheed and his former defence minister, but the charges against them were unclear, a senior official of Nasheed's Maldivian Democratic Party (MDP) said.

An arrest warrant has been issued for him and his former defence minister, MDP official Adam Manik told Reuters. We have no idea (what the charges are).

Police said on state TV on Wednesday night that protests led by Nasheed after his ouster were an act of terrorism.

MDP officials said police and soldiers were on their way to arrest Nasheed, who had just met with a Commonwealth delegation in the Indian Ocean archipelago to mediate in the political crisis that followed his resignation on Tuesday.

The tumult this week is far away from the thousands of upmarket tourists who visit the islands each week. Up to one million people visit the Maldives each year, and tourism forms a major chunk of its GDP.

Nasheed was injured on Wednesday when police broke up protests against his ouster, and there was no immediate word on his whereabouts. He said earlier he was forced to quit at gunpoint.

There were guns all around me and they told me they wouldn't hesitate to use them if I didn't resign, he told a news conference.

Vice President Mohamed Waheed Hassan Manik was installed as president and has said he will form a government of national unity.

Protests against Nasheed's government started after he ordered the military to arrest the criminal court chief justice, saying he was blocking multi-million dollar corruption and human rights cases against the allies of Maumoon Abdul Gayoom, president for 30 years until he was replaced by Nasheed.

The Progressive Party of the Maldives, led by Gayoom, said in a statement it was appalled by Nasheed's desperate attempts at insurgency to return to power barely 24 hours after his resignation.

Nasheed must know that militancy and chaos do little to repair his tarnished image, it said.

Western diplomats said they wanted all political parties, including Nasheed's, to back down and join the unity government.

We want to take the politics off the streets and cool the rhetoric down, a European diplomat based in Colombo told Reuters.

The United Nations and Western governments have given the transfer of power at least an apparent seal of approval, based on their public statements.

However, John Rankin, British High Commissioner to Sri Lanka and the Maldives, said he was concerned for Nasheed.

We are aware of reports of an arrest warrant issued for President Nasheed, Rankin said. 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.

(Writing by Raju Gopalakrishnan; Editing by Nick Macfie)