A car bomb exploded near Iraq's southern Shi'ite city of Basra Wednesday, killing at least four people and wounding more than a dozen others.<br/> <br />The attack comes against the backdrop of escalating violence in Iraq.<br/> <br />Sunni rebels from an al Qaeda splinter group overran the Iraqi city of Tikrit Wednesday.<br/> <br />Insurgent forces have also taken control of Mosul, Iraq's second biggest city.<br/> <br />Their rapid advance against the Shi'ite-led government in Baghdad, is raising concerns in the U.S., says State Department spokeswoman Jen Psaki.<br/> <br />(SOUNDBITE)(English) JEN PSAKI STATE DEPARTMENT SPOKESPERSON SAYING:<br/> <br />"The situation is certainly very grave on the ground. We are working with Iraqi leaders across the country to support a coordinated response. You can expect that we will provide additional assistance to the iraqi government to combat the threat from ISIL but I am not in a position to outline that further at this point."<br/> <br />In May alone nearly 800 people were killed
