Several army tanks and armoured vehicles have been seized by armed Sunni tribesmen opposed to Yemen's Shia Houthi fighters, officials say.
The announcement on Friday came as the Houthis in control of the capital Sanaa intensified security measures on the eve of a ceremony commemorating Prophet Muhammad's birthday.
Officials said the seizures happened after clashes broke out on Thursday night in the eastern city of Marib between the tribesmen and government troops.
The tribesmen suspected that the soldiers were heading to join the Houthis, who have been gathering outside of Marib for several weeks.
Six soldiers and two tribesmen were killed in the clashes, officials said, speaking on condition of anonymity because they were not authorised to speak to the press.
The Houthis are backed by loyalists of Ali Abdullah Saleh, the former Yemeni president.
They have overrun Sanaa and other cities in a power grab that has plunged Yemen into turmoil.
Separately, Yemeni activists have accused a Houthi group of trying to take control of the city of Taiz and posting publications described as sectarian.
The activists removed the publications that were in some of the city's streets.
In Sanaa, Houthis plastered the streets with green decorations while preparing to hold a large festival in a captured army base to commemorate the birthday of Prophet Muhammad on Friday night.
The celebrations have drawn the ire of many Yemenis, who say that Houthis are trying to appease disgruntled residents after months of violence in the city and across the country.
The Houthis have boosted security measures and increased public deployments in Sanaa for fear of attacks by al-Qaeda.
Celebrations in Sanaa come two days after a similar event turned bloody when a suicide bomber struck in the central city of Ibb, leaving at least 37 dead and nearly 50 injured.
Source: Al Jazeera and agencies