A Yemeni shot dead an American and a Canadian employed at a Western oil firm in the Arab state today and killed himself, a Yemeni official said.
The official said another Yemeni man was killed and a third Western man wounded in the attack, carried out by a carpenter working on the premises of the unnamed firm in the oil-rich Marib province.
The nationality of the wounded Westerner was not known.
US firm Hunt Oil is the only oil firm operating in Marib.
An official at the Canadian embassy in Saudi Arabia, which also handles Yemen, said the mission was aware of the incident. The US embassy in the Yemeni capital of Sanaa said it would issue a statement.
Last December, a Yemeni gunman believed to have links to al-Qaeda killed three US missionaries at a hospital. Last week, citing increased tensions in the Middle East, Canada warned its citizens not to travel to Yemen, where many people carry firearms.