A Saudi Arabian diplomat has returned to Riyadh after being released by kidnappers in Yemen where he spent three years as a hostage.

Abdullah al-Khalidi, Saudi consul in Aden, was seized in March 2012 and later appeared as a hostage in videos released by al Qaeda in the Arabian Peninsula (AQAP) calling on Riyadh to do more to free him.

The Interior Ministry did not say in its brief statement how Mr Khalidi came to be released, except that it was a result of "intensive efforts" made by the kingdom's intelligence agency.

AQAP and its parent organisation al Qaeda have sworn to bring down the Saudi state and Riyadh has worked closely with the US to undermine the groups' operations in Yemen by sharing intelligence.

Saudi Arabia, Yemen's most powerful neighbour, fears growing instability there might give more space for AQAP to operate and launch more operations like a cross-border raid it carried out in August in which eight people were killed.