The United Nations envoy to Iraq has condemned the killing of over a dozen people near a town in the western province of Anbar.Martin Kobler, the special representative of UN Secretary General Ban Ki-moon in Iraq, denounced the killings as a “cold-blooded murder,” Ban’s spokesman Martin Nesirky said on Thursday. The incident took place near the town of Nukhaib on June 5 after unidentified gunmen stopped the victims at a fake checkpoint set up along the main highway connecting Iraq to Saudi Arabia. The assailants then opened fire on them. No group has claimed responsibility for the attack so far. The UN envoy to Iraq also offered condolences to the families of the victims, calling on Iraqi authorities to take swift and decisive action to bring the perpetrators of the crime to justice. There has been a recent upsurge in violence across Iraq. Authorities say Qatar and Saudi Arabia are to blame for involvement in the violence. On May 30, Kobler also warned that “systemic violence is ready to explode at any moment” in Iraq. The United Nations said on June 1 that a total of 1,045 people were killed and nearly 2,400 others were injured in the incidents of violence across Iraq in May. Iraqi Prime Minister Nouri al-Maliki has blamed militant groups and the remnants of the former Ba’athist regime for the recent wave of violence.