BAGHDAD - The United States says the main body of insurgents in Iraq has shifted towards Syria, as Marines pressed an offensive in the huge border region of Anbar.
Marine Corps Lt Gen James Conway said in Washington that the centre of resistance had moved towards the border area since the fall of Fallujah.
The statement came, however, as four suicide bombs killed at least 59 people in Tikrit, Baghdad and Hawija, near Kirkuk.
US Marines were reported to have killed 75 rebels in the first day of their Anbar offensive.
Conway said the rebels appeared better trained than other insurgents and some wore military uniforms.
"There are reports that these people are in uniforms, in some cases wearing protective vests. And there’s some suspicion that their training exceeds that of what we have seen with other engagements further east," Conway said.
The general did not offer further details on the uniforms.
In a statement, the Marines Corps called the region a known smuggling route, sanctuary for foreign fighters and a place through where they funnel weapons and equipment for attacks in Baghdad, Ramadi, Fallujah and Mosul.
Conway said no Iraqi government forces were fighting as part of the US task force, but did not rule out them joining the offensive.
The latest and deadliest suicide bombing yesterday came when a car bomber blew up his vehicle in Tikrit among a crowd of mainly Shi’ite migrant workers from south Iraq.
Police said at least 28 people were killed and more than 60 wounded.
In the town of Hawija, southwest of the strategic oil city of Kirkuk, a man strapped with explosives walked into an army recruitment centre and blew himself up, killing 25 people and wounding 34, police said.
A suicide car bomb also exploded outside a police station in the southern Baghdad suburb of Dora, killing four people and wounding dozens. Another hit the Mansour district, killing two policemen and a civilian.
Insurgents also hit back by kidnapping the Anbar province’s top official, Raja Nawaf, who had only become governor a few days ago, and four bodyguards.
The kidnappers are believed to be supporters of the al Qaeda leader in Iraq, Abu Musab al-Zarqawi.
That hostage drama played out in Iraq’s guerrilla heartland as a deadline set by an insurgent group holding 63-year-old Australian engineer Douglas Wood expired.
In a video shown on al-Jazeera television last week, Wood looked distraught as two masked insurgents pointed rifles at him. His head was shaved and he appeared to have a black eye.
The insurgent group, the Shura Council of the Mujahideen in Iraq, demanded Australia withdraw its troops from Iraq.
Australian Foreign Minister Alexander Downer said there had been no word about Wood’s fate since the deadline passed.
"We haven’t heard anything ... we just don’t know what to think and we are continuing to work on the case."
One of Iraq’s most feared insurgent groups, the army of Ansar al-Sunna, said it was to release a video of a Japanese citizen captured in an ambush in a convoy carrying 12 Iraqis and five foreigners in Anbar.
It claimed that all those in the convoy except security worker Akihito Saito, were killed.
Both Australia and Japan have troops in Iraq. A new batch of 450 Australian soldiers is due to arrive soon in southern Iraq, taking the total of Australian troops in and around Iraq to about 1,400.
Japan has around 550 soldiers in Iraq, which is a largely symbolic deployment as they are not allowed to take part in combat.
The past few weeks have seen a sharp escalation in guerrilla attacks.
Even before last night’s blasts, a surge of guerilla attacks had killed 300 Iraqis in two weeks and injured hundreds more.
Iraqi officials say Zarqawi’s fighters regrouped as the country’s new leaders bickered for three months following January elections.
US troops have also suffered heavy losses in the surge in attacks, with 14 dead in Iraq since Saturday.