SANAA: Gunmen on Saturday seized Yemeni President Abdrabuh Mansur Hadi's chief of staff, whose nomination as prime minister last year was rejected by Shia militiamen controlling the capital, an official said.

“An armed group set up a checkpoint in Hada,” a southern district of Sanaa, and “captured (Ahmed Awad bin) Mubarak with his companions,” an official from the national dialogue secretariat told AFP.

Mubarak is secretary general of the national dialogue on a political transition following the 2012 resignation of veteran president Ali Abdullah Saleh after a bloody year-long uprising.

The senior politician was “driven away to an unknown location,” the official said, adding that the abductors “are suspected of being (Shia) Huthi militiamen”.

Yemen has been dogged by instability since Saleh's ouster, with the Huthis and al Qaeda seeking to fill the power vacuum.

Mubarak, a southerner, was one of the representatives in the dialogue of the Southern Movement, which seeks autonomy or secession for the formerly independent south.

Hadi appointed him as prime minister in October, but Mubarak turned down the job following strong opposition by Huthi fighters who overran Sanaa on September 21, and by Saleh's General People's Congress Party.

The Huthis are widely believed to be backed by Saleh.

The UN Security Council in November slapped sanctions, including a visa ban and asset freeze, on Saleh and two rebel commanders for threatening peace.

The turmoil has raised fears that Yemen, which neighbours oil-rich Saudi Arabia and lies on the key shipping route from the Suez Canal to the Gulf, may become a failed state similar to Somalia.