BAGHDAD, Aug. 20 (Xinhua) -- The United Nations Assistance Mission for Iraq (UNAMI) on Thursday strongly condemned the killing of two civil society activists in Iraq's southern province of Basra.

"The killing of Dr. Reham Yaqoub last night and Tahseen Oussama a week ago presents a serious threat to security and stability in Basra," Jeanine Hennis-Plasschaert, the special representative of the United Nations Secretary-General for Iraq, said in a statement.

"The citizens of Basra should not live in such an atmosphere of terror and threat, and greater action by the authorities is urgently required to hold the perpetrators accountable, and to put an end to this cycle of violence," said Hennis-Plasschaert, who also heads the UNAMI.

On Wednesday, unknown gunmen opened fire on a sport utility vehicle (SUV) carrying four women on a street in the city of Basra, some 550 km south of Baghdad.

The attack resulted in the killing of Yaqoub, a female doctor who works in Basra Hospital and also a civil society activist who supports the anti-government protests in Iraq which demanded comprehensive reform, fight against corruption, better public services, and more job opportunities.

The attack also resulted in the killing of another woman and the wounding of the two others in the vehicle.

Two days ago, Iraqi Prime Minister Mustafa al-Kadhimi sacked the police chief of Basra province, as well as the head of the National Security Service, due to repeated security violations and assassinations in the province recently.

Last Friday, unknown gunmen assassinated another civil society activist, Tahseen Oussama, with silenced weapons in Basra, said the provincial police.