Confrontations erupted between the military police and tribesmen in Marib Province but no casualties were reported, a tribal source was quoted as saying on Sunday.
The clashes in Madghal district broke out on Sana'a-Marib road when the security forces wanted to take three injured tribesmen from the Al-Jadaan tribe to hospital, the source said.
The tribesmen were wounded in an exchange of gunfire with the security forces two days ago when bandits from the tribe set up an illegal checkpoint and tried to hijack gas trucks.
The security forces thwarted attempted hijackings and clashed with the tribesmen. Two were killed and three others were hurt.