"Mosul and Kirkuk have fallen," Major Rumi Nielson-Green told AFP at the Central Command (Centcom) base.

"Coalition forces are inside the cities," she said, adding "they are mostly special operations forces."

She said members of the Iraqi 5th Corps in and around the Mosul surrendered to coalition troops.

"They made a very wise decision to live for a free Iraq rather that die for Saddam Hussein's regime," Nielson-Green said.

Kurdish fighters earlier reached the centre of Mosul, the main northern Iraqi city, where they kept a low profile, an AFP reporter said.

They were seen in the city around 0725 GMT, but an hour later they seemed to have disappeared.

In Kirkuk, captured by Kurdish and US forces, the situation was spiralling out of the control of local Kurdish chiefs and several people were killed amid pillaging and score-settling, the city's Kurdish governor, Rizgarali Hamgam, told AFP.

"Special forces and elements of the 173 Infantry Division continue to secure Kirkuk," said Nielson-Green.

She said coalition forces were in control of Kirkuk's airport.

Another Centcom spokesman said there was still "a lot of uncertainty" in northern Iraq.

"There is still a lot of hard work to be done, we anticipate sporadic resistance," said US Navy Ensign David Luckett.

US-led forces also continued bombing Tikrit, the northern hometown and stronghold of Iraqi President Saddam Hussein, he said.

"We continue to shape the battle space," he said, explaining that this meant preparing the ground for "a successful mission" involving minimal loss of life.

US military officials say there are few ground troops around Tikrit at this stage, and that operations are focused largely on airstrikes against military and government targets.

The officials say there are several command and control facilities in Tikrit, a city seen as a symbol of Saddam's 24-year rule.

Saddam was born in a community near Tikrit, 170 kilometers (105 miles) north of Baghdad, and the region is considered his principal power base.

SPACE.WIRE