(VOVworld)-The Iraqi army says it has launched a major offensive to retake Tikrit from Sunni rebels, amid conflicting claims over who controls the city's university. The main ground operation, which began on Saturday, followed heavy fighting in the city between Sunni rebels and Iraqi special forces, who were trying to establish a foothold at the university campus. Iraqi military sources said they had captured the university but rebels led by the Islamic State in Iraq and the Levant said they had successfully repelled the attack. The same day, Iraq’s police reported that 25 members of the security forces died and 22 others injured in clashes between the Iraqi government’s forces and rebels in southern Baghdad.