Yemen's Houthi rebels on Sunday claimed to have captured hundreds of Saudis, including mercenaries from Pakistan, Iraq, and Sudan, during attacks over the past three days in the southern Saudi region of Najran.
"The enemy has suffered heavy losses during the operation," a statement released by the group's spokesperson Abdul Salam read, and noted that "among the captives are hundreds of Saudis, including officers and mercenaries from Sudan, Pakistan, and Iraq, among others."
"The Nasr Min Allah (a victory from Allah) operation is one of the best and greatest fruits of the steadfastness of Yemini people in confronting the aggression," the statement added.
Watch: Houthis release footage said to show border attack and Saudi forces surrendering
The development comes hours after the group broadcast video footage they said was of a deadly attack in the Saudi region of Najran that killed hundreds of soldiers, with thousands of others surrendering before the armed group, including three brigades of troops led by former-Pakistan Army chief Raheel Sharif.
A spokesman of the Houthis, Yahya Saree, described the attacks as an ambush on the Saudi forces that then developed into an "all-out" cross-border offensive that trapped the troops inside Saudi Arabia, Al Jazeera reported.
"More than 200 were killed in dozens of [missile and drone] strikes while trying to escape or surrender," Saree said.
The spokesperson added that the offence committed 72 hours earlier had targeted three "enemy military brigades", leading to the capture of "thousands" of troops, including Saudi army officers and soldiers, and hundreds of armoured vehicles.
The army brigades were a part of the Islamic Military Counter Terrorism Coalition (IMCTC), commanded by the former Pakistan Army chief. The IMCTC is an intergovernmental counter-terrorist alliance of the Middle Eastern countries, united around military intervention against the Islamic State and other counter-terrorist activities.
Sharif was named the IMCTC's first commander-in-chief in January 2017 after his retirement as the Pakistan Army general in 2016.
The released video showed armoured vehicles being hit by blasts and soldiers surrendering before the Iran-aligned rebels.
Catherine Shakdam from UK-based think-tank 'Next Century Foundation' told Al Jazeera there was no reason to doubt what the Houthis were saying.
"The video and images coming through are affirming the statement. It's a pivotal point in this war that now Yemeni are moving on Saudi land. It's quite interesting to see with all the talk of a grand Saudi coalition that Saudi is very much alone in this fight," Shakdam was quoted as saying.
The Houthi rebels in Yemen on Monday warned of more attacks on Saudi Arabia's oil infrastructure, two days after drone strikes that interrupted much of the kingdom's oil production that heightened tensions between Iran and the United States.
The rebel group has launched a missile and drone attacks into Saudi territory before, but never anything on that scale.
The attacks on the Kingdom's oil giant Saudi Aramco forced the shutdown of facilities at Abqaiq and Khurais, which process most of the crude oil produced by Saudi Arabia, which supplies about a tenth of the worldwide total.
The Houthi rebels in Yemen on Monday warned of more attacks on Saudi Arabia's oil infrastructure.