At least four people have been killed in a car bomb blast in a majority Shia area of the Iraqi capital, Baghdad, Iraqi officials say.The medical sources and security official announced on Saturday that the explosion took place near a clinic in Al-Amin District in southeast Baghdad. At least 20 people, including four children, were also injured in the attack. Another car bomb explosion hit a police convoy in the northern city of Mosul, killing one policeman and injuring two others. On Friday, 16 Iranian pilgrims were killed after a bomb attack hit their convoy near the city of Baquba. There has recently been an upsurge in violence across Iraq, and the authorities say Qatar and Saudi Arabia have had a hand in some of the incidents. On June 1, the United Nations said a total of 1,045 people were killed and 2,397 injured in violent incidents in Iraq in the month of May. On May 30, UN envoy to Iraq Martin Kobler warned that “systemic violence is ready to explode at any moment.” He also urged Iraq's political leaders to “engage immediately to pull the country out of this mayhem.” Iraqi Prime Minister Nouri al-Maliki has said that militant groups and the remnants of the former Ba’athist regime are responsible for the latest wave of violence.