CENTRAL IRAQ, April 2 (IslamOnline.net & News Agencies) – U.S. ground troops tackled Iraq's elite Republican Guard in a major battle south of Baghdad for the first time in the nearly two-week-old military aggression on the Arab country.

The battle came as President Saddam Hussein called for Jihad to boot out the U.S.-led invading forces, whose bombs rained down again on his presidential compound in central Baghdad early Wednesday, April 2, reported Agence France-Presse (AFP).

In their push towards Baghdad, U.S. forces were "fully engaged" for the "first time" with Republican Guard troops near Karbala, about 80 kilometers (50 miles) south of the capital, said a defense official in Washington, speaking on condition of anonymity.

The attack, primarily involving the U.S. 3rd Infantry Division, followed days of intensive bombing of the Guard's Medina, Baghdad, Hammurabi and Al Nida divisions, Iraq's best trained, best armed and most loyal forces.

U.S. troops crossed through the Karbala gap, a major gateway towards Baghdad, in what appeared to be a long-awaited push on the Iraqi capital, an AFP correspondent at the scene reported.

Members of the 3rd Infantry Division appeared to have met little resistance as they crossed the gap between Karbala city and a nearby lake.

General Richard Myers, the chairman of the Joint Chiefs of Staff, earlier claimed attacks from the air and ground had reduced the combat capability of two Republican Guard divisions by more than half.

He apologized for the killings of seven women and children at a U.S. checkpoint in An-Najaf, in central Iraq.

The U.S. Central Command said it could not confirm charges by an Iraqi civilian that 15 members of his family had been killed in an attack by an Apache helicopter near Hilla, to the east of Karbala.

Local hospital director Murtada Abbas said 33 civilians, including children, were killed and 310 wounded in Anglo-American air strikes early Tuesday, April 2, of a residential suburb of Hilla.

A spokesman for the International Committee of the Red Cross in Baghdad described the coalition bombardment of the town as a "horror" that had left dozens of "smashed corpses".

The offensive on Baghdad's defensive lines was launched in the face of controversy in Washington over whether the Pentagon had deployed sufficient forces to press the battle for the Iraqi capital and protect supply lines to their rear.

Thousands of troops from the U.S. 4th Infantry Division, expected to reinforce U.S.-led invasion troops in Iraq, began arriving in Kuwait but could take weeks to reach the battlefield, a U.S. military official said.

And in the southern town of Basra, seen as key to controlling the southeast, British troops said they were awaiting reinforcements before making a final push to take the city.

The British press, quoting senior military sources at U.S. Central Command in Qatar, said Wednesday that coalition forces were poised for an attack on Baghdad that could begin within 48 hours.

The drive on the Iraqi capital came amid international concerns over the rising toll of Iraqi civilian casualties.

U.S. Defense Secretary Donald Rumsfeld denied rumors of

A huge plume of smoke rises from the Republican Guard palace in Baghdad during air strikes

third party peace plan, saying the only thing that would be discussed was the regime's unconditional surrender.

The bombing of Baghdad continued apace early Wednesday, with an attack on the Republican Palace complex, the largest of Saddam's eight palaces, at around 3:05 am (0005 GMT).

Bombs or missiles also poured down on Republican Guard defenses to the south of the city at the same time and again around 6:50 am (0350 GMT).

The bombardment came just hours after Saddam called on his countrymen to launch Jihad against the invaders battling their way towards the Iraqi capital.

"Hit them, fight them! They are evil aggressors," Saddam said in a text read on Iraqi television by Information Minister Mohammad Said al-Sahhaf.

"This aggression is against religion, property, people and dignity," he said of the US-led invasion, adding "this is why jihad is a duty."

Officials in London said a British soldier was killed on duty in southern Iraq, taking to 26 the British death toll since the start of the war.

U.S. authorities say 46 U.S. soldiers have been killed, 38 of them in combat. Seven troops have been taken prisoner and 14 are missing.

Two U.S. airmen were rescued by helicopter Wednesday after their F-14 crashed in Iraq following mechanical failure, Central Command said.