Sana’a, Asharq Al-Awsat—Houthi militants are on course to expand into southern Yemen after overrunning the strategically-important city of Rada’, south of the capital Sana’a, on Friday, encountering little government resistance.

Local news reported that clashes between Shi’ite Houthi fighters and local residents continued in the town of Yareem in Ibb province on Saturday following anti-Houthi protests in the region. At least 20 people were killed in clashes between Sunni tribesmen and Houthi rebels in the city of Ibb on Friday amid fears of sectarian escalation in the country.

Shi’ite fighters already in control of Sana’a and the northern and central parts of Yemen have now taken control of the key city of Rada’ in the southern Al-Baydah province. The capture of Rada’, which serves as a gateway to a number of other Yemeni provinces, opens the way for the Houthis to sweep across the volatile south of the country, an area where the Shi’ite militia has not historically enjoyed a strong presence.

A ministry source, speaking to Asharq Al-Awsat on the condition of anonymity because he was not authorized to brief the media, said that Yemeni Ministry of Interior staff had received instructions not to resist the Houthi militia. The source claimed that the instructions had been signed by Minister of Interior Maj. Gen. Hussein Al-Tarb.

Dozens were killed and injured in the city of Ibb on Friday after followers of the Sunni Al-Islah party, backed by tribal fighters, attempted to drive Houthi militants from the city.

Hundreds of fighters from the city reportedly exchanged fire with militants from the Houthi Ansar Allah group while local media reported that Ibb residents are fleeing the violence en masse.

Houthis entered the city last week after they struck a ceasefire deal with the local authorities, a move that has infuriated local Sunni tribes.

Local sources informed Asharq Al-Awsat that Houthi fighters launched a surprise attack on the residence of Ibb security chief Col. Fuad Al-Attab and the local radio station in retaliation to demands to disarm by the city’s security services.

Prior to the latest violence, representatives of local tribes had gathered outside the house of Ibb’s mayor, demanding the dismantling of Houthi checkpoints that have been established in the city.

Elsewhere, Houthis began to dismantle protest camps in the capital Sana’a on Friday as part of the Peace and National Partnership Agreement struck with Yemeni President Abd Rabbuh Mansur Hadi, aimed at resolving the political and security crisis in the country.

Hadi spoke with US President Barack Obama by phone on Friday during which Obama reaffirmed Washington’s full support for Yemen’s security, stability and unity. Obama called on all Yemeni political parties to work together to accelerate the implementation of the agreement.