Washington (AFP) - Two captive Americans were freed Wednesday in Yemen as more than 200 supporters of the country's Huthi rebels were allowed to return home, in an apparent swap involving Saudi Arabia and Oman.

The White House announced that humanitarian worker Sandra Loli and businessman Mikael Gidada had been freed by the Iranian-backed Huthi rebels who control much of Yemen including its capital Sanaa.

The rebels also sent back the remains of a third American, Bilal Fateen, the White House said. Secretary of State Mike Pompeo said Fateen died in captivity, without providing details.

Robert O'Brien, the national security advisor, stopped short of saying there was a swap but thanked Saudi King Salman and Omani Sultan Haitham bin Tarik Al-Said "for their efforts to secure the release of our citizens."

President Donald Trump "continues to prioritize securing the release and repatriation of Americans held hostage abroad," O'Brien said in a statement.

"We will not rest until those held are home with their loved ones," he said.

Trump, struggling in polls ahead of November 3 elections, has highlighted efforts to free hostages and punish hostage-takers, with his campaign pointing to backing by the parents of Kayla Mueller, a relief worker killed after being abducted by Islamic State extremists in Syria in 2013.

Little had been known about the Americans held in Yemen until the announcement of their release.

Richard Boni, the husband of Loli, said his wife had traveled to war-battered Yemen to deliver safe drinking water and had been held hostage for 16 months.

"Today is a day we have long hoped for," he said in a statement.

The Wall Street Journal, quoting a senior White House official said to have arranged the deal, said Gidada was involved in business and taken about a year ago.

Huthi leaders have previously announced detentions of foreign humanitarian workers, accusing them of spying, and have been accused of diverting some of the badly needed aid sent into the country.

Stranded in Oman

The Huthis -- who enjoy religious ties, political backing and at least some military support from US arch-enemy Iran -- said they had been trying to bring home 240 of their supporters stranded in neighboring Oman.

They had traveled to Oman -- which frequently plays the role of broker in the turbulent region -- two years ago for medical treatment, the rebels said.

"Thanks to God, about 240 fellow countrymen, who had been wounded and stranded, arrived in Sanaa on board two Omani planes," said Huthi spokesman Mohammed Abdel Salam.

"Among them were the wounded people who left for Muscat during the Sweden talks, and the United Nations did not return them according to the agreement," he said, referring to the UN-sponsored peace process. 

Senior Huthi political official Mohamed Ali al-Huthi accused the Saudi-led coalition that has led a bloody campaign against the rebels of previously refusing to let the group travel back.

"Today we were pleased to receive some wounded brothers who were stuck outside the country as a result of the brutal and continuous siege on our country. The coalition obstructed their exit and entry, one of its war crimes against Yemenis," al-Huthi said in a tweet.

The Saudi-led coalition, which backs the fledgling internationally recognized government in Yemen, did not immediately comment on the release or whether there was a swap.

Saudi Foreign Minister Prince Faisal bin Farhan was holding talks Wednesday in Washington, where he criticized the Huthi rebels.

"The Iranian regime continues to provide financial and material support to terrorist groups, including in Yemen where the Huthis have launched more than 300 Iranian-made ballistic missiles and drones towards the kingdom," he said, speaking next to Secretary of State Mike Pompeo.

Saudi Arabia has faced widespread criticism over the deaths of civilians in its offensive in Yemen, which the United Nations has described as the world's worst humanitarian crisis.

Some 3.3 million people have been displaced and 2,500 schools have been put out of commission, most of them due to attacks, according to UN figures.

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