At least four tribal fighters of whose supporting the armed forces in the battles against Al-Qaida militants were killed in a suicide bombing in Yemen's Abyan province on Monday, the Defense Ministry said.
fifth fighter was injured in the incident, which occurred early morning in the Um Sorra in the Lawder district, the ministry said.
"Two militants detonated their bomb car at a checkpoint of the tribal fighters amid precise checking process in this area," it said.
"The fighters at the checkpoint wanted to check the car, but the militants refused and exploded their car immediately".
One of the militant bombers was in woman dress, the ministry said.
Scores of militants have been killed in the past few days in the ongoing battles to clear militants from more areas in Abyan province.
Many tribal fighters joined the national forces, which have recently stepped up the offensive against Al-Qaida in Abyan province. The forces have retook some areas, which were seized last year including Lawder.
Hundreds of militants including senior leaders have been killed and injured, amid ongoing battles to retake the most important strongholds of Al-Qaida: Zinjibar, the capital of Abyan and Jaar.
The US is providing direct support to the Yemeni army, with drones killing many militants, especially key leaders.