CAIRO — Yemeni rebels said Sunday they carried out a major assault on forces of a Saudi Arabian-led coalition near the border between the two nations, and released footage that they said shows hundreds of captured troops, including Saudi officers, and destroyed Saudi military vehicles.

The rebels also said they killed or wounded 500 coalition soldiers.

The Saudi-led coalition has yet to respond to the rebels’ claims. If confirmed, the assault would be one of the most significant victories for the Iranian-aligned rebels, known as Houthis, in the nearly five-year civil war gripping the Middle East’s poorest nation. 

The Houthi-owned Al-Masirah television network broadcast footage showing a long, snaking line of what the rebels said were captured troops walking in rugged terrain. Many of the men, who apparently surrendered to the rebels, were dressed in flip flops and the traditional sarong-like clothing worn in Yemen and parts of Saudi Arabia. A handful wore tan camouflage uniforms. At least two said on camera that they were citizens of Saudi Arabia.

Other images showed burning armored vehicles with Saudi markings and weapons that the Houthis said they seized. Houthi fighters are shown apparently launching attacks on coalition troops, clashes that left what appears to be corpses in Saudi military uniforms.

The Washington Post could not independently verify any of the images.

If claims about the attack are found to be credible, it is certain to fuel more concern in Washington and Riyadh that Iran is behind the rebels’ growing military capabilities, which in recent months have included drone and cruise missile attacks on Saudi soil. 

It would also bolster the Houthis’ claims that they had orchestrated the largest ever assault on Saudi oil facilities, on Sept. 14, which temporarily shut down oil production and rattled the global economy. The Trump administration and Riyadh say the attack did not come from Yemen; they blame Iran, which has denied the accusation.

The fresh tensions come amid reports in the Wall Street Journal that Saudi Arabia has agreed to a partial cease-fire deal involving four areas in Yemen, including Sanaa, the capital. That follows a surprise offer on Sept. 20 by the Houthis to halt drone and missile attacks on Saudi Arabia if the coalition stops launching airstrikes. Days later, 15 members of one family, including seven children, were reportedly killed in an apparent coalition airstrike in southern Yemen.

A Houthi military spokesman told journalists in Sanaa that the offensive occurred near Saudi Arabia’s southern Najran region, close to the border with northern Yemen’s Houthi-dominated Saada province. Spokesman Yahya Sahria did not say when it occurred.

Sahria said the rebels had defeated three military brigades and captured more than 2,000 troops and “hundreds” of armored vehicles. He said Saudi army officers and soldiers were among the captured.

Other Houthi officials reached by phone in Sanaa said that the vast majority were Yemeni soldiers fighting with the coalition and that about a dozen were Saudi nationals.

The coalition of Sunni Muslim countries joined Yemen’s conflict in March 2015 to restore the country’s internationally recognized government after it was driven out of Sanaa by the Shiite Houthis. The coalition also seeks to thwart Shiite Iran’s growing regional ambitions, which include its alliance with the Houthis.

The United States and other Western powers are backing the coalition with intelligence, logistical support and billions of dollars in arms sales. The conflict has deepened a humanitarian crisis that has left more than 80 percent of Yemen’s nearly 30 million people in need of assistance. Millions are on the brink of famine.

Yemen’s border with Saudi Arabia has been a key battle zone. 

Ali al Mujahed in Sanaa contributed to this report.