Two men were shot dead on Wednesday when Saudi security forces stormed a house to arrest a wanted man in the Qatif region, the focal point of unrest by an anti-regime movement.
Activists have demonstrated against what they perceive as systematic discrimination against minorities in the kingdom. But Saudi Arabia, the world's top oil producer, has avoided the sort of broad uprising that has ousted Arab autocrats elsewhere.
Saudi authorities were trying to arrest one of 23 men who the government said were wanted for stirring unrest in Qatif, where 15 people have been killed since November in clashes and protests.
"He and his companions opened fire on the security forces and, in dealing with the situation as it required, it resulted in the death of the wanted man ... and one of his companions, and the wounding of two others and the arrest of a third," Saudi Press Agency reported, citing the government security spokesman.
The wanted man was identified as Khaled Abdulkarim Hassan al-Labad. Activists in the village of Awamiya in Qatif, the center of Saudi unrest, said a third man was killed in a car. They distributed photos showing wounds in his neck.
A Saudi Interior Ministry spokesman described that as an unrelated incident in which one man died and another was injured after their vehicle was fired at by unknown assailants.
"It was a separate incident and an investigation is ongoing," the spokesman said. Preliminary information suggests a person wanted by the security forces for criminal activity in Qatif may have been involved in the attack, he added.
Activists say protest rallies have been fueled by the 15 deaths in Qatif, arrests of protesters and a heavy security presence. Activists say some of those killed were shot during peaceful protests.
Qatif is in Eastern Province, the hub of Saudi oil output.
Saudi authorities say that the deaths have all been the result of exchanges of fire after security forces were shot at. One of those killed was a security official.
"The security forces will not hesitate to pursue wanted people and troublemakers on the ground and to arrest them," the security spokesman was quoted as saying by the press agency.