As questions are raised about Pentagon's planning and the progress of the war in Iraq, the United States has decided to increase its troop presence in the conflict zone.

About 30,000 soldiers of the 4th Infantry Division and other units based at Fort Hood, Texas, will be deployed soon, CNN quoted Pentagon officials as saying.

Another 100,000 soldiers -- most of them in armoured divisions and mechanised units -- will arrive in Iraq in April, it said.

A spokesman for the US Central Command said on Friday that coalition forces have not underestimated the strength of Iraq's Fidayeen Saddam and other paramilitary groups.

CNN quoted him as saying that "severe blows" have, in fact, been inflicted on the Iraqi forces.

In what is likely to irk some Pentagon officials, Lieutenant General William Wallace, the commander of V Corps, admitted: "The enemy we're fighting is different from the one we'd war-gamed against, because of the paramilitary forces."

The New York Times quoted him as saying, "We knew they were here, but we did not know how they would fight."

According to British forces, Iraqi militiamen are firing at thousands of people who are trying to escape from the southern city of Basra.

They are using heavy weapons like mortars to put the people down, a British military spokesperson told BBC.

A British military leader said his forces have placed themselves between the militiamen and civilians.

The previous two British claims about a civilian uprising in Basra have turned out to be false.

As the battles rage, twelve more US Marines have gone missing in the last 24 hours around Nasiriya.

US military officials said 11 of them are with the 2nd Marine Expeditionary Brigade. Another 14 Marines from the brigade have sustained injuries, CNN quoted the officials as saying.

A fierce fight is also going on in and around Baghdad. A US Army source told CNN that the Medina Division of the Republican Guard, which defends the capital's southern perimeter, has been badly hit by bombings.

Overnight, a US Air Force B-2 stealth bomber dropped two 4,700lb satellite-guided bunker-buster bombs in downtown Baghdad.

Iraqi Information Minister, Mohammed Saeed al-Sahaf said the bombs have killed seven people and injured 92.

Iraqi Defence Minister Sultan Hashem Ahmed said that the coalition troops would have to fight their way into Baghdad.

"The enemy must come inside Baghdad and that will be its grave," BBC quoted him as saying.

He said he expects the coalition forces to surround the capital within five or 10 days.

But amidst all the gloom, there is some good new for the Iraqis. A British ship has docked at Umm Qasr with 650 tonnes of aid, including food, medicine and fresh water.

The Sir Galahad was supposed to dock on Wednesday, but got delayed due to storms and discovery of mines.

The United Nations has also reached a broad agreement on restoring the oil-for-food programme in Iraq.