A top US diplomat arrived in the Maldives on Saturday seeking to help resolve a deepening political crisis sparked by the ousting of the Indian Ocean nation's first democratically elected president.

Mohamed Nasheed, who came to power in 2008, says he was forced to quit on Tuesday in a coup led by mutinous army and police officers who threatened him with violence unless he stepped down as leader of the famous holiday islands.

He was replaced by his vice president Mohamed Waheed, whom Nasheed accuses of being party to the conspiracy to topple him.

The US assistant secretary of state for South Asian affairs, Robert Blake, will seek to clarify how power was transferred during a visit to Male, capital of the nation of 1,200 islands, the state department announced.

"Ambassador Blake will meet the president as well as the opposition during his 12-hour visit," a US official in Male said.

Nasheed's exit from office followed months of protests over high prices and calls for more religiously conservative policies in the nation of Sunni Muslims.

Since stepping down, Nasheed has called for fresh elections and threatened protests if police continue targeting his party members and figures in his former administration.

Rioting erupted across the country on Wednesday when Nasheed said he was the victim of a military-backed coup and his party's senior members were beaten during a rally in Male.

At least 18 police stations were torched and dozens of vehicles, court houses and government buildings were destroyed in remote islets of the archipelago, police say.

Police confirmed they were carrying out mass arrests of troublemakers while Nasheed said 350 people linked to his administration had been detained within three days of his resignation.

New President Waheed has rejected Nasheed's demand for elections.

"Simply because an ex-president wants an election we can't have one just like that," Waheed's spokesman Masood Imad said. "There is a constitutional process."

Imad said Waheed had no intention of clinging to power and would hold the next election when it is due, by November 2013.

New protests would spell further instability and damage for the country, which depends on the thousands of high-end travellers who visit its pristine islands each year.

Nasheed's efforts to force Waheed to step down suffered a major blow on Thursday when Washington announced it recognised his successor's administration.

Nasheed, who had become an environmental celebrity for urging global action to tackle climate change that he said threatened to submerge his island nation, voiced deep disappointment at the US announcement.

The US later appeared to step back from its earlier declaration.

"We will work with the government of the Maldives, but believe the circumstances surrounding the transfer of power need to be clarified," US State Department spokeswoman Victoria Nuland said in Washington.

"We also suggest all parties agree to an independent mechanism to do that."

"He (Blake) will see all of the major players and have a chance to talk about an appropriate way forward and reconciliation."

Nasheed said on Friday recognition of the new Male administration would not resolve the crisis.

A UN special envoy, Assistant Secretary General Oscar Fernandez-Taranco, arrived in the Maldives on Friday and met both sides.

A delegation from neighbouring India was also visiting while an EU mission was headed for the tropical nation.

"India is a very close friend of the Maldives and wants the best for Maldives. I hope India can play a key role," Nasheed said.

Presidential spokesman Imad said police would be obliged to execute an arrest warrant for Nasheed only if there was a risk he would not appear in court to answer charges yet to be made public.

"He can go anywhere in the country, but he can't leave," Imad said.