The government forces including thousands who were lately trained in Saudi Arabia on Monday raided the Al-Anad military base and Labouzah brigade in Yemen's southern city of Lahj, sources from the popular resistance said.
The battles with the Houthi militants at the two sites are continuing, they said, expecting the forces will retake the two sites in coming hours.
Scores of Houthi militants and pro-former president forces backing them have been killed and injured in the battles, they said.
There were also casualties within the popular resistance whose fighters are backing the forces, they said, without giving figures.
The Saudi-led Arab coalition is providing direct support to the forces including intensified airstrikes against the Houthi militants and dissident forces, they elaborated.
Recently, the forces retook the adjacent city of Aden from the Houthis after months of battles and Houthi siege.
In Taiz, the government forces with support from the coalition and the popular resistance are waging fierce battles against the Houthi militants and forces backing them in areas including the Sabir Mountain and Wadi Al-Dhabab districts, locals said.
In Sabir, the forces have retaken key positions after deadly battles, they said. Scores from both sides have been killed and injured in the past few days, they added.
Confrontations between the forces and the Houthis are ongoing in other cities such as Abyab, Dhali, Baidha, Marib and Shabwa.
Meantime, the coalition, which has been bombing the Houthi militants since March, is backing the Yemeni forces in order to retake all southern and middle regions from the militants in a few weeks, well-informed sources said today.
The Houthis ousted the UN-backed transition government early this year and have expanded by force across the country sparking a civil war.
Thousands have been killed and injured in the conflict which has also left 80% of Yemen's population in need of emergency aid.