- Shi'ite rebels captured an army base and several soldiers on Monday in clashes with the army and tribesmen that killed 10 people and threatened a fragile truce in northern Yemen, rebel and officials said.
Yemen's President Ali Abdullah Saleh accused the rebels, known as Houthis after the name of their leaders' clan, of trying to ignite a new war with the government.
Both the government and the rebels confirmed that a number of soldiers had been taken hostage at the Zuala army base in the flashpoint north district of Harf Sufyan, but neither side would give an exact number of how many men were seized by the Houthis.
Among those killed in the clashes were rebels, soldiers, and tribesmen from the Ibn Aziz tribe which allied with the government against the Houthis in the northern war. Both sides declined to say how many men they lost.
Yemen agreed a truce with Houthis in February to halt a war that has raged on and off since 2004 and displaced 350,000 people. But instability still threatens Yemen, neighbor to top exporter Saudi Arabia, which was briefly drawn into the conflict last year when rebels seized Saudi border areas.
Houthi rebels complain of socio-economic and religious discrimination by the government, accusations it denies.
Tensions between the rebels and the Ibn Aziz tribe, from the same Zaidi sect of Shi'ite Islam but which sides with the government, have increased in past months. Clashes last week were the bloodiest since the truce and drew in government forces.
Separately, security forces in southern Yemen killed three men believed to be al Qaeda members in continuing security sweeps following the militant group's recent attacks on state security forces, a local security official said on Monday.
Ahmed al-Maqdisi, head of security in the southern province of Shabwa, said the three men were suspected of participating in an attack on Thursday on a security convoy in Shabwa that killed five soldiers and was blamed on al Qaeda.
Al Qaeda's regional wing based in Yemen had previously focused its high-impact strikes on foreign targets, but has started to also aim them at government forces in response to a recent U.S.-backed crackdown on al Qaeda.
Western powers fear the militant group could be exploiting growing instability in Yemen to use the country as a launchpad for attacks abroad.
Yemen also faces a separatist movement in its south and is under Western and Saudi pressure to quell domestic conflicts in order to focus on al Qaeda.
On Sunday, gunmen killed six Yemeni soldiers in Shabwa, an oil-producing province. It was the fourth assault since June attributed to al Qaeda's regional Yemen-based arm that hit state targets, including intelligence and police offices.