Shiite rebels Wednesday seized a city in central Yemen seen as a strategic link to the south, security and tribal source said, further expanding the territory under their control.
And nine people were killed when a bomb exploded near a rebel office in the capital, overrun by the insurgents last month, police said.
Yemen has fallen deeper into turmoil since an uprising ousted strongman Ali Abdullah Saleh in 2012 after a year of unrest, with rivals, including the Huthi rebels and Al-Qaeda, battling each other.
The Huthis captured Radmah -- on a road linking Sanaa with the main southern city Aden -- after 24 hours of fighting against local tribesmen, a security official told AFP.
Radmah is in Ibb province, where the rebels have been locked this month in battles with mostly-Sunni tribesmen.
After easily overrunning the capital in September, the Huthis moved on to the Red Sea port city of Hudeida as well as Shiite-populated Dhamar and entered Ibb, the provincial capital.
The rebels, from the mountainous north, are seeking greater political clout in impoverished Yemen, which is located next to oil kingpin Saudi Arabia and key shipping routes in the Gulf of Aden.
Yemen is a key US ally that has allowed Washington to conduct drone strikes against Al-Qaeda on its territory, and the fighting has raised fears of it collapsing into a failed state.
Radmah is a stronghold of the Muslim Brotherhood-linked Al-Islah party, whose supporters have been resisting the Huthi advance.
Tribal sources said nine fighters from both sides were killed during the battle for the city.
Further southwest, in Ibb city, dozens of rebels stormed the main security headquarters overnight and members of the security forces fled, an official said.
With the fall of Ramdah, the Huthis now virtually control Ibb province with the exception of Udain, which is in the hands of Al-Qaeda and allied tribesmen, a local official said. In Rada, in the neighbouring province of Baida, 12 Huthis were killed in an attack by Al-Qaeda suspects, tribal sources said.
The Huthis, who had long been concentrated in their northern highlands where Shiites form a majority, have been facing fierce resistance from local tribesmen as well as Al-Qaeda.
In Sanaa, meanwhile, an explosive device planted close to a Huthi office at Amran Roundabout, killed nine people, police and witnesses said.
Several others were wounded.
And two Huthis were shot dead by gunmen on a motorbike in Mahjaza, in Marib province, east of the capital, tribal sources said.
The rebels are believed to be eyeing control of oil fields in Marib.  
The rebels appear unmoved by a weekend call from President Abdrabuh Mansur Hadi to "immediately pull out" of all seized areas, including the capital.
But political sources in Sanaa told AFP tribes allied to the rebels were expected to meet there Friday following calls by rebel leader Abdulmalik al-Huthi to discuss ways to return the country to normality.