Yemeni troops on Saturday shot dead five al-Qaeda suspects disguised as women who fired at a soldier during a checkpoint inspection of their Saudi-bound bus, officials said.

Another suspect was wounded along with the driver in the shooting at Harad, a town 15 km from the Saudi border, the officials said, adding two of those killed were Saudis.

"As one of the soldiers climbed on board the bus for an inspection, one of the suspects opened fire and wounded him, prompting shooting from other soldiers at the checkpoint," said a government official who gave the casualty toll.

All of the six men had been dressed in black robes and wore the niqab, a face-covering veil commonly worn by women in Yemen, the official in Harad told AFP.

A suicide belt and arms were also found on board the bus, and the wounded suspect and driver are being questioned, the security official said.

"The men are suspected of affiliation with al-Qaeda and were heading north towards Yemen's border with Saudi Arabia," he told AFP.