Shia Houthi rebels in Yemen have abducted the chief of staff of President Abdrabbuh Mansour Hadi.

Ahmed Awad bin Mubarak and two of his guards were seized early on Saturday in the centre of the capital Sanaa.

The Houthis said they abducted him to prevent a UN-brokered deal between them and the presidency being broken.

The country has been plagued by instability since mass protests forced former President, Ali Abdullah Saleh, to step down in 2011.

Scores of people have been killed in clashes between the Houthis and Sunni militants.

A statement from the Houthis warned President Hadi of "a series of special measures" they were prepared to take to prevent the breaking of the deal.

The two sides agreed a truce in September last year after mounting clashes in Sanaa.

Negotiations are under way to secure Mr Bin Mubarak's release.

Houthi rebels blocked his appointment as prime minister last year.

The group was formed in 2004 to win greater autonomy for their home region of Saada, and to protect followers of Zaidism, the branch of Islam they adhere to.

Their critics say they are a proxy for Iran, a charge the rebels deny.

A video purportedly from al-Qaeda in Yemen (AQAP) said it planned and financed the attack on the Charlie Hebdo offices in France that killed 12, but did not provide evidence to support its claims.

There have been separate protests in Sanaa about the rising violence in the country and against the French satirical magazine Charlie Hebdo's decision to publish an image of the Prophet Muhammad.

BBC