Yemeni security and tribal officials say several tanks and armored vehicles have been seized by armed tribesmen rival to the country's Shiite rebels.

Officials say the seizures came after clashes broke out Thursday night in the eastern city of Marib between tribesmen and army troops. They say the tribesmen suspected that the soldiers were heading to join the Shiite rebels 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 authorized to speak to the press.

The Shiite rebels known as the Houthis are backed by ousted President Ali Abdullah Saleh. They have overrun the capital and other cities in a power grab that has plunged Yemen into turmoil.