Smoke rises from the periphery of Baghdad as evening approaches Saturday.

WASHINGTON -- U.S.-led coalition troops have advanced more than 150 miles into Iraqi territory and have crossed the Euphrates River using existing bridges, the Pentagon said Saturday. "We must remain prepared for potentially tough fights as we go forward," said Maj. Gen. Stanley McChrystal during a Pentagon briefing.  Meanwhile in Kuwait, where it was already early Sunday, at least eight people were wounded, four to six of them seriously, when two blasts went off in a tent containing members of the U.S. Army 1st Brigade, Time magazine reporter Jim Lacey told CNN. Lacey said the military was calling it a terrorist attack, and that U.S. infantry were securing the area.  The commander of the U.S.-led war on Iraq said Saturday that operations were being conducted in north, south and west Iraq and in Baghdad, where witnesses reported new explosions.

Warplanes on board the USS Theodore Roosevelt and USS Harry S. Truman, stationed in the Mediterranean, are on a 24-hour launch schedule, according to CNN's Gary Streiker, on board the Roosevelt. 

Streiker reported that missions Saturday targeted an AM radio station in central Iraq and a presidential palace compound in western Baghdad. 

A giant plume of smoke could be seen rising into the night sky over Baghdad on Saturday at 7:22 p.m (11:22 a.m. EST), followed by a flurry of anti-aircraft fire. Ambulances rushed to the scene of the blasts, local TV reported. 

About an hour earlier, Roland Huguenin-Benjamin, with the International Committee of the Red Cross, said he heard "two or three powerful explosions." Within minutes, all was quiet and the only sound was a call for prayer from the mosque next door, he said. A cloud of thick, black smoke has hung over the city for much of the day. 

In his first briefing since the start of "Operation Iraqi Freedom," Franks told reporters that between 1,000 and 2,000 Iraqi troops have surrendered and were taken into custody, and "thousands more have laid down their weapons and have gone home." 

A CentCom spokesman said U.S.-led forces Saturday captured the southern Iraqi town of Nasiriya, key crossing point on the Euphrates River for U.S. Marines racing across the southern Iraqi desert headed for Baghdad. 

The U.S. Army 3rd Infantry Division's 7th Cavalry Regiment swept northward to within about 160 miles of Baghdad before it was bogged down by an exchange of fire with Iraqi troops to the north. 

CNN's Walter Rodgers, who is with the 3rd Squadron of that regiment, reported that a detachment of Iraqi soldiers put up surprisingly strong opposition to the armored force. Rodgers said Army commanders used long-range artillery strikes to take out the Iraqi forces instead of engaging them in a head-to-head tank battle. A U.S. Air Force A-10 "Warthog," or "Thunderbolt," was called in to provide close air support when surviving Iraqi forces fired on reconnaissance helicopters. 

So far, in the first days of the military campaign, 21 deaths have been confirmed among coalition troops -- 14 Britons and seven Americans. 

Other developments
• About 35 cargo ships carrying equipment for the U.S. Army's Fourth Infantry Division, originally slated to move into Iraq from northern Turkey, will be moved instead through the Suez Canal and then on to the Persian Gulf and Kuwait, Pentagon officials said Saturday. Turkey did not agree to allow the U.S. to use its territory to attack Iraq, so the Fourth will be part of the follow-on force instead of the original combat force. 

• A Tomahawk cruise missile might have missed its Iraqi target, instead landing in southwest Iran, Pentagon officials said Saturday. Military officials are investigating the possibility. Hundreds of cruise missiles were used during the coalition bombing attacks Friday. 

• CNN's Nic Robertson, who was expelled from Iraq along with three other CNN staff members, said Friday's punishing aerial campaign seemed to focus on Iraq's presidential palace, across the river from their hotel. He said the explosions appeared limited to governmental areas. The number of direct hits the palace took during the seven-minute barrage was "incredible," Robertson said. Iraqi officials said two major buildings -- the "Peace Palace" and the "Flower Palace" -- were turned "into ruins" and that more than 200 civilians were injured. 

• Kurdish forces told CNN's Brent Sadler that over the next seven days, thousands of U.S. airborne troops are expected to fly into northern Iraq from eastern Jordan, bypassing Turkish airspace. • There are conflicting reports whether Turkish troops have crossed the border into Iraq. The Turks contend they need a buffer zone in northern Iraq to "manage the humanitarian situation" -- partly by keeping Kurdish refugees from crossing over into Turkey. U.S. officials do not want Turkish troops moving into Kurdish-controlled areas of northern Iraq for fear there will be clashes between Turkish and Kurdish troops.  • Four people were shot dead and dozens more were injured Friday as police clashed with demonstrators trying to storm the U.S. Embassy in Yemen, witnesses told CNN, on a second day of worldwide protests against the war in Iraq. (Full story, new protests Saturday)