The United States will continue to aid Saudi-led forces in Yemen, as the Senate failed to override President Donald Trump's veto against a resolution to end Washington's military involvement in the deadly war.

The lawmakers needed a two-thirds majority in both the Senate and House of Representatives to overturn the White House's objection to the law. But on Thursday, senators came 14 votes short of the 67 required for the veto override.

That effectively kills the resolution and ends Congress's push to halt US assistance to Saudi Arabia and its allies, which launched the war in Yemen in 2015.

"So long as the United States participates in the military campaign with the Saudis while not offering any meaningful pressure to get to a political settlement, we are complicit in those deaths," Democratic Senator Chris Murphy said before the vote on Thursday.

"A quarter of a million people are going to die in the next several months inside Yemen - from starvation and disease and malnutrition - due to a military campaign that we are a part of."

'A quarter of a million people are going to die in the next several months ... due to a military campaign that we are a part of' - US Senator Chris Murphy

In early April, lawmakers in both the House and Senate passed the legislation, triggering for the first time a 1973 law that gives Congress the power to end US military interventions it did not authorise.

Trump, however, blocked the bill, calling it an "unnecessary, dangerous attempt" to weaken his authority.

The war in Yemen started in 2015 when Saudi Arabia, the United Arab Emirates and their regional allies began a massive bombing campaign in Yemen to push back against the country's Houthi rebels and restore the government of Abd Rabbuh Mansour Hadi.

The war has brought the already-impoverished country to the verge of famine and caused outbreaks of preventable diseases, leaving millions of people in need of humanitarian assistance.

The conflict and its effects will have killed more than 230,000 Yemenis by the end of the year, a recent UN report revealed.

US Senator Bernie Sanders, the lead sponsor of the resolution, sent copies of the UN report to his colleagues to "understand how devastating the crisis is in Yemen", he said in a video message on Wednesday.

"The United States should not be supporting a catastrophic war, led by a despotic regime with a dangerous and irresponsible foreign policy," Sanders said on the Senate floor on Thursday.

Yemen death toll to surpass 230,000 by end of 2019: UN report Read More »

The worsening humanitarian crisis in Yemen and the murder of journalist Jamal Khashoggi at the hands of Saudi government agents late last year have intensified opposition to the war in Congress.

Washington provides logistic support to the Saudi-led coalition in Yemen - assistance that experts say is vital to the kingdom's military campaign there.

Earlier on Thursday, Senate Majority Leader Mitch McConnell, slammed the resolution, contending that the effort to halt US assistance would actually worsen the humanitarian situation.

"Abandoning our Yemeni, Emirati and Saudi partners, just as diplomatic efforts are starting to make progress, is hardly the way to give them the confidence to take the hard diplomatic steps that are necessary," said McConnell, the top Senate Republican, as he urged lawmakers to uphold the veto.

Supporters of the resolution, however, condemned Saudi Arabia's policies before the vote.

Senator Chris Van Hollen said the Gulf kingdom has continued with its human rights violations, even after the backlash that followed the murder of Khashoggi, citing the recent execution of dozens of activists.

Van Hollen also highlighted the humanitarian crisis in Yemen, saying that apart from devastating the country, the war has failed to push out the Houthis and curb Iranian influence in the region.

"The crown prince's and Saudi Arabia's military adventurism has been a major strategic blunder," the senator said.