Yemeni security officials and witnesses say four civilians have been killed in a third day of fighting between Shiite rebels and Sunni militiamen in the capital Sanaa.

Officials said the battle Saturday pitted the Shiite rebels, known as the Hawthis, against militias and army units allied with the Muslim Brotherhood's Islah party. Security and health officials said mortar shells hit civilian homes and a hospital.

The fighting took place on the road to the international airport and near a major military base, the state television building and on two university campuses, north and west of the capital.

Three Hawthis were killed and two soldiers were wounded in clashes further south.

All officials spoke on condition of anonymity because they were not authorized to brief reporters.