A member of the Iraqi security forces uses binoculars as he keeps watch in Tikrit March 30, 2015.[Photo/Agencies]

On Monday, the troops reportedly retook control of the main hospital building, which is part of the government compound, and took new positions in the surrounding area as they are heading toward the central part of Tikrit.

Late on Wednesday, Iraqi Prime Minister Haider al-Abadi announced that the Iraqi forces started the final phase to liberate Tikrit and the rest of the northern parts of Salahudin province with the assistance of the international coalition air support.

The battles to free Tikrit from IS militants were stalled for about two weeks as the militants planted thousands of bombs and booby-trapped dozens of buildings and cars.

Since March 2, some 30,000 Iraqi troops and thousands of allied Shiite and Sunni militias have been involved in Iraq's biggest offensive to recapture the northern part of Salahudin province, including Tikrit and other key towns and villages, from IS militants.

Large parts of the province have been under IS militant group control since last June, after bloody clashes broke out between Iraqi security forces and the group.