Security officials in Yemen say two gunmen riding a motorcycle have killed a Shiite-rebel representative on the country's national dialogue conference.

The officials said Friday that Abdel Karim Gadban, a representative of Ansar Allah, the political arm of the Shiite Hawthis rebels, was killed while leaving a mosque in the capital, Sanaa. They spoke on condition of anonymity as they were not allowed to brief reporters.

Ansar Allah leader Abdel Karim el-Khaywani said the killing was an attempt to hinder the work of the national dialogue conference, which is tasked with mapping out the Arab nation's future.

Hawthis rebels also have been fighting for months with ultraconservative Salafis in Yemen's restive north. A government-brokered cease-fire has been repeatedly broken since it was established earlier in November.