U.S. commanders have ordered a pause of four to six days in a northward push toward Baghdad because of supply shortages and stiff Iraqi resistance, U.S. military officers said on Saturday.
They said the "operational pause," ordered on Friday, meant that advances would be put on hold while the military tried to sort out logistics problems caused by long supply lines from neighboring Kuwait.

Food rations have been cut for at least one frontline U.S. unit and fuel use has been limited.

The U.S.-led invasion force would continue to attack Iraqi forces to the north with heavy air strikes during the pause, battering them before any attack on Baghdad, they said. The officers declined to be named.

"We have almost out-run our logistics lines," one officer said at a U.S. unit at the northernmost stretch of the advance in central Iraq. Some units have advanced to within 80 km (50 miles) of Baghdad, but are almost 500 km from Kuwait.

Some military units further to the rear were still pushing forward, however, Reuters correspondents traveling with the troops reported.

At war headquarters in Qatar, the main spokesman for British forces said the attackers needed to prepare for a next phase but did not confirm a formal four- to six-day pause.

"I would not necessarily call it a pause," Group Captain Al Lockwood told Sky News.

"SHAPING THE BATTLEFIELD"

"It is simply a matter of shaping the battle space, shaping the battlefield, getting up troops equipped with all the assets they will need for the next part of the campaign," he said. He said the overall war plan was "on track and on time."

In Washington, a U.S. defense official said: "There is nothing at all to suggest that we are just going to sit there for four to six days and do nothing."

On Friday, Britain's Army chief, Mike Jackson, dismissed suggestions that the campaign had become bogged down after a few days of quick advances from Kuwait since the invasion started on March 20. But he spoke of a need to pause.

"Armies cannot keep moving forever without stopping from time to time to regroup, to ensure their supplies are up," he told a London news conference. "It's a pause while people get sorted out for what comes next."

In one frontline U.S. infantry unit, soldiers have had their rations cut to one "meal ready to eat" packet a day from a normal three until supply trucks can get through.

And the U.S. military officers said that use of gas-guzzling armored vehicles had been restricted to save diesel. No resupply is expected for 24 hours.

Items like batteries for radios are also limited and soldiers and Marines have been told to conserve the ones they have. Fresh water is not a problem.

Stiffer-than-expected resistance from Saddam Fedayeen militias in towns along the advance lines has made running supply convoys a real problem, particularly from the southern city of Nassirya northwards.

Convoys this week through Nassiriya have been ambushed.

President Saddam Hussein's government has played down the apparently lightning advance by the U.S.-led forces, saying that most of the gains have been across tracts of desert while skirting major towns along the route.

Near the city of Najaf, the U.S. military is building a desert airstrip able to handle C-130 transport aircraft to help bypass the need to bring in new supplies by road. Najaf is 160 km (100 miles) south of Baghdad.