A gunman opened fire inside a Yemen mosque on Friday, killing eight people in the second attack in a month targeting worshippers in the ancestral land of Al-Qaeda leader Osama bin Laden.
In separate violence, unknown assailants fired rockets at an oil pipeline in the south of the country, witnesses said.
"A man opened fire on worshippers in a mosque in the village of Kahal," 100 kilometres north of the capital Sanaa, killing eight people and wounding nine, an official told AFP.
Weekly Friday prayers were under way in the mosque in Amran province when the shooting happened, said the official.
The suspect "is believed to be mentally unbalanced," he added.
The official Saba news agency gave a lower death toll, saying seven people were killed in the attack and that 12 were wounded. Three of the injured are in a serious condition, the agency said. Saba earlier said 11 were hurt.
Saba identified the suspect as Abdullah Saleh Zaid al-Qahali, 24, and said he had been arrested and was being questioned about the attack.
Amran police chief Tahar al-Ashwal told Saba the initial investigation has shown that the shooting was "criminally" motivated and linked to a dispute over a plot of land between the suspect and another man.
The man involved in the row was killed in the shooting, Ashwal said.
Amran governor Kahlan Mujahid Abu Shuareb said the gunman used a machine gun and confessed that he had wanted to kill "everyone".