US President Donald Trump’s Republican allies in the House of Representatives have blocked a vote on a measure that sought to end Washington’s support for Saudi Arabia’s brutal war on Yemen.

The still Republican-led lower chamber of Congress voted 201-187 on Wednesday afternoon to approve a rule for floor debate on a bill that aimed to take the gray wolf off the endanger species list.

Also included in the measure, however, was an unrelated clause that barred debate on the US military’s involvement in the conflict.

The House Rules committee snuck the extraordinary clause in the wildlife bill on Tuesday, in order to block voting on a resolution by Democratic Representative Ro Khanna which invoked the 1973 War Powers Resolution to “remove US armed forces from hostilities in the Republic of Yemen that have not been authorized by Congress”.

Since it was introduced under the War Powers Resolution, Khanna’s measure should have had privileged status meaning the committee could not hold it up by the majority for more than 15 days and after that the measure had to be subject to floor vote.

The Wednesday vote allows Republicans to block all measures to end Yemen war until January, when the new Congress takes over.

“It’s unfortunate that the Republicans broke precedent and blocked our resolution to end US involvement in the war in Yemen. They are abdicating congressional oversight duties on their way out of power,” Khanna tweeted.

He then pledged to continue his efforts in the new Congress, where Democrats would be the majority party in the House after scoring a crucial victory in the midterm elections.

Representative Eliot Engel, a top Democrat who is likely to lead the House Foreign Affairs Committee in the next Congress, blasted the “outrageous” Republican move in a statement

“It’s outrageous and unprecedented that House Republicans are shutting down debate about America’s involvement in the war in Yemen...It’s wrong for Republicans to stop the House from taking up these critical issues,” he said.

While the Republican victory will ease pressure on Riyadh and its powerful lobby in Washington, there are other similar measures that are expected to give the perpetrators of the years-long war more headache.

Congressional opposition to the US participation in the war has been growing over the past months.

Many lawmakers have expressed concern about the growing civilian death toll from the bombing campaign against Yemen, which is led by Saudi Arabia, the United Arab Emirates, Bahrain and other close allies of the Riyadh regime.

Last week, the US announced it would no longer refuel Saudi warplanes over Yemen, but continues to supply arms, intelligence and logistical support to Riyadh.