Officials: Gunmen kill envoy of Yemen's northern rebels in the capital, Sanaa

Yemeni officials say gunmen have killed the top envoy of the country's northern rebels in the capital, Sanaa.

The officials say Ahmed Sharaf Eddin was assassinated early Tuesday in his car. They spoke on condition of anonymity because they were not authorized to talk to media.

Sharaf Eddin represented Yemen's Hawthi rebels, who are members of a Shiite sect, in the so-called National Dialogue talks.

The talks are meant to draw up a blueprint for a new constitution under a transition plan in the wake of the country's 2011 uprising.

The Hawthis fought a bloody six-year insurgency that ended with a cease-fire in 2010 but a recent escalation in fighting between them and ultraconservative Sunni tribesmen has turned several northern cities into war zones.