Forces loyal to Yemen's former president seized government buildings in the southern city of Aden on Monday after a five-hour battle, sources said, escalating a civil conflict that threatens to split the country in two.

The militias supporting Abd-Rabbu Mansour Hadi wrested control of several buildings in the city from security forces allied to the Houthi movement, the sources said.

The country's north is dominated by the Shiite Muslim Houthis, who seized power in the capital Sanaa last month, while in the south forces loyal to Hadi and separatists seeking to restore the former South Yemen appear to be in control.

Sources said fighters loyal to Hadi's brother seized Aden's television building, its main power station, the intelligence headquarters and the free zone authority offices in five hours of clashes overnight with forces led by a general seen as allied to the Houthis.

Aden's governor, Abdel-Aziz bin Habtour, in remarks carried by the Defense Ministry's 26 September news website, confirmed the clashes but denied the television station had been seized by the Hadi loyalists.