The rebels have been pushing out from the mountains of the far north to areas closer to Sanaa to expand their hoped-for autonomous unit in a promised federal Yemen.
In another indication of the growing unrest in the country, a German citizen kidnapped in the capital on Friday is being held in a tribal region of the eastern Marib province, a foreign ministry official said today.
The Huthis seized the town of Huth and Khamri village -- the seat of the Hashid tribal chief, as tribal defence lines crumbled, local sources and witnesses said.
"Members of Hashid backed by takfiris (Sunni extremists) have fled."
Tribal chief sheikh Hussein al-Ahmar ordered his fighters to evacuate his family's farm in Khamri and set it ablaze, witnesses said, adding that the tribesmen have retreated to neighbouring areas.
The witnesses saw dozens of horses and vehicles fleeing from the farm and said scores of tribesmen have been captured by the advancing rebels.
The violence in Amran province dates back to January 5, and dozens of people have been killed in the fighting, including 60 on Friday alone.
Divisions within the Hashid tribe could have contributed to the defeat, sources said, pointing out that some have sided with the Huthis.
The division is a result of an ongoing dispute between the Hashid chief sheikh Sadeq al-Ahmar and former president Ali Abdullah Saleh, who also belongs to the vast Hashid tribe.
Ahmar had sided with nationwide Arab Spring protests that forced Saleh to step down in February 2012 after 33 years in power.
In addition to taking on the northern tribes, the Shiite Huthis have also been battling hardline Sunni Salafists who established religious schools in parts of the north.