A member of Iran’s Islamic Revolutionary Guard Corps was smuggled into Yemen last year and named the ambassador to the country’s Houthi-rebel-controlled areas. Now, the Houthis want to send him back to Tehran, Middle Eastern and Western officials said.

The Houthi forces have asked Saudi Arabia, which maintains a sweeping air blockade of Yemen’s capital, to let the top Iranian diplomat in the country immediately fly back to Iran, a request seen by Saudi officials as a sign of strains between Tehran and the militant group.

The diplomat, Hassan Irloo, has been deeply involved in helping the Houthis with battlefield planning, but his influence in Yemen has bolstered a negative perception in the country that the militant force answers to Tehran, according to regional officials. After seven years of civil war, the Houthis remain in control of Sana’a, the capital, and govern much of the country’s north.

“Irloo has become a burden for them,” said one regional official. “He’s a political problem.”

The Saudis told Houthi leaders that they wouldn’t let Iran fly a plane to Yemen to get Mr. Irloo, according to regional officials. Instead, the officials said, Mr. Irloo could only fly out on a plane from Oman or Iraq and would only be allowed to leave if the Houthis freed some high-profile Saudi hostages.

Iranian officials didn’t respond Friday to requests for comment. Houthi leaders didn’t respond to questions seeking comment.

Iran and the Houthis have deepened their ties ever since the Yemeni militants seized control of Sana’a in 2014 in the early days of the war. Iran welcomed a Houthi ambassador to Tehran in 2019 and then sent Mr. Irloo to Sana’a last year.

Riyadh and Washington have accused Iran of providing the Houthis with ballistic missiles, drones, training and advisers that have transformed the militant group into a more potent threat to Saudi Arabia and the region. United Nations inspectors have repeatedly found Iranian-made parts in the wreckage of drones and missiles fired at Saudi Arabia. Tehran denies that it provides the Houthis with weapons.

The Houthi request to the Saudis comes amid a resurgence in fighting in the seven-year war.

Saudi Arabia has stepped up airstrikes in Yemen after U.S. and U.N. efforts to broker a cease-fire hit a wall. Saudi Arabia has started targeting Iranian advisers and members of Lebanese militant group Hezbollah who have been working alongside Houthi forces in Yemen, according to regional officials.

Houthi fighters are determined to seize Marib, an oil-rich Yemeni town on the Saudi border that Riyadh is struggling to keep from falling to the Iran-backed forces. The fight for Marib is viewed by both sides as a decisive battle that could determine who emerges victorious from a war that has created a protracted humanitarian crisis.

In recent days, Houthi leaders asked Saudi officials for permission to put Mr. Irloo on a flight back to Tehran, the regional and Western officials said. Houthi officials assured Riyadh that they wouldn’t replace Mr. Irloo with a new Iranian diplomat.

Riyadh took this as a sign that the Houthis were trying to distance themselves from Tehran’s influence, according to regional officials. Houthi leaders told Riyadh that Mr. Irloo needed to leave to get better medical treatment after contracting Covid-19, the officials said. But regional officials said Mr. Irloo was still holding meetings in Yemen and said there were no signs he had Covid-19.