Yemeni security officials say a rocket fired by Shiite rebels has killed six civilians in the war-torn city of Taiz.

They say the Wednesday strike hit a residential area inside Taiz. It comes one day after six civilians were also killed outside the city, which is known as the cultural center of Yemen.

Clashes between rebels and forces loyal to President Abed Rabbo Mansour Hadi have been ongoing for nearly two years.

The officials spoke on condition of anonymity because they weren't authorized to brief reporters.

The war in Yemen has raged since the rebels, known as Houthis, seized the capital, Sanaa, in September 2014. A Saudi-led coalition has waged an air campaign since March 2015 aimed at restoring Hadi's government. The northern region remains under Houthi control.