Iraqi security forces and their allies battled "Islamic State" militants on Thursday in a second day of fighting against the militant group in the birth city of late former dictator Saddam Hussein.

IS fighters had stormed into Tikrit - which is located around 130 kilometers north of Baghdad - last June in an offensive that stopped outside the capital. They have since occupied a number of palaces, built under Saddam, and used them as their headquarters.

"Now we are moving to the second phase of our plan," Iraqi Defense Minister Khaled al-Obeidi told reporters in the province of Salaheddin.

"We are very keen for our losses to be as low as possible. Time is on our side, we have the initiative," he added.

The offensive to retake Tikrit began 10 days ago with a group of more than 20,000 Iraqi troops and Iranian-backed Shiite Muslim militias, supported by local Sunni Muslim tribes advancing from the east and on the banks of the Tigris.

Recapturing the city is seen as key in weakening the extremist IS group, which seized much of northern and western Iraq last summer and now controls about a third of both Iraq and Syria.

IS has carried out a number of attacks elsewhere in the country, launching over a dozen suicide car bombings against army positions on Wednesday in Ramadi, about 90 km (55 miles) west of Baghdad.

Also on Wednesday, at least 22 Iraqi soldiers were killed in a blast in Anbar, in what appeared to be friendly fire. An Iraqi official said the explosion was caused by an air strike carried out by US-led coalition forces, but the US said the only coalition attack had been miles from the site of the blast.

sb/bw (AP, Reuters, AFP)