A court controlled by Yemen’s Houthi rebels has sentenced 21 men to death for allegedly spying for the Saudi-led coalition which backs the war-torn country’s government, according to a report.

The Houthi-run al-Masirah TV’s report on Saturday did not identify the defendants, but said they are all Yemenis, reports Xinhua news agency.

There was no comment yet from the coalition or the Yemeni government.

The ruling by the court in the Houthi-held capital Sanaa was the latest in a series of closed-door trials of political opponents held by the Houthis.

Yemen has been mired in civil war since late 2014, when the Iran-backed Houthi group seized control of several northern provinces and forced the Saudi-backed government of President Abd-Rabbuh Mansour Hadi out of Sanaa.

The Saudi-led military coalition intervened in the Yemeni conflict in March 2015 to support Hadi’s government.

The war has killed tens of thousands of people, displaced nearly 4 million and pushed more than 20 million to the brink of famine.