Iran’s envoy to Yemen’s rebel Houthi movement has died of COVID-19 after being repatriated last week, Iran’s Foreign Ministry said on Tuesday, blaming unnamed countries for his delayed transfer from the Yemeni capital Sanaa, Reuters reported.

According to the report the ambassador, Hasan Irlu, “was evacuated in poor condition due to delayed cooperation from certain countries,” ministry spokesman Saeed Khatibzadeh told state media.

The spokesman appeared to be referring to Saudi Arabia, which along with Iraq helped in Irlu’s transfer on board an Iraqi plane, according to a Houthi spokesman.

A Saudi-led coalition that has been battling the Iran-aligned Houthi movement for more than six years has imposed a sea and air blockade on areas the group controls.

The Saudi government media office CIC did not immediately respond to a Reuters request for comment.

Saudi Arabia and Iran, the region’s Sunni Muslim and Shi’ite powerhouses, launched direct talks this year at a time when global powers are trying to salvage a nuclear pact with Tehran and as U.N.-led efforts to end the Yemen war stall.

Last December, the U.S. Treasury blacklisted Irlu and described him as an official of Iran’s elite Quds Force, the overseas arm of Iran’s Revolutionary Guards and a pillar of Iranian efforts to project power in Yemen, Syria and elsewhere.

“We have lost a great friend,” Houthi deputy foreign minister Hussein al-Ezzi said, offering condolences on Twitter.

Two Yemeni political sources close to the movement and a foreign source said Irlu had recently kept a low profile due to illness and political tension. The Yemeni sources said some Houthi leaders had resented perceived “interference” by Irlu, read the report.

A Houthi spokesman did not immediately respond to a Reuters request for comment.

According to Reuters the Saudi-led coalition intervened in Yemen in 2015 against the Houthis after the movement ousted the internationally recognised government from Sanaa.