Kut, Iraq ? One year after invading Iraq, U.S. Army Staff Sgt. Jorge Velez was meant to be heading home today from Baghdad. Instead, the platoon sergeant was smack in the center of this restive Shiite heartland Saturday, kicking in doors and staging raids as Killer Troop hunted down supporters of America’s newest Iraqi enemy, Muqtada al-Sadr.

About 600 U.S. 1st Armored Division forces rushed into town Thursday, Velez among them, two days after allied Ukrainian troops abandoned it to about 500 of al-Sadr’s Mahdi Army militiamen. By nightfall the Americans were in their fiercest combat in months — withering rounds of rocket-propelled-grenades and Kalashnikov assault fire that wounded three soldiers and tied them down for hours as they fought across a bridge over the Tigris River to reach this city of 250,000.

At 1 a.m. today Iraqi time, Brigade Commander Col. Rob Baker declared that U.S. forces had broken the back of the Madhi Army in Kut and U.S. troops were in command.

“They’re no longer an organized resistance,” he said, describing three days of combined air, armor and ground assaults that “hit them with a sledgehammer and put them in perspective.”

The soldiers in Saturday’s raid were serious as they searched the empty ruins of an old Baath Party compound for the enemy. But when the work was done, the mood became bitter among the 2nd Armored Cavalry Regiment — because they had gotten word on the eve of their departure that their one-year tour would continue, indefinitely.

Tougher fights may lay ahead in the young militant sheik’s strongholds in Najaf and Karbala.

“It’s hard,” said Velez, 30, of Caguas, Puerto Rico. “It’s time to go. A year is a long time in Iraq. You’re tense all the time.”

Saturday in the Persian Gulf, troops were taking the shrink-wrap off the 1st Armored Division attack aircraft, which had been packed onto ships before last week’s southern Shiite rebellion, to put them back into service.

In short, the troops that had survived a year of deadly roadside bombs and sniping attacks in Baghdad were back in battle again, and they were disappointed.

“Me too. But I’m pretty certain that the soldiers understand their mission here. And they’re going to finish the job, finish the fight here,” said Brig. Gen. Mike Scaparrotti, who commanded the rapid-reaction force that rushed south as Sadr’s militiamen were overrunning Iraqi police and coalition compounds manned by Ukrainian, Polish, Spanish and other forces across the south last week.

“Motivation is down,” Velez said. “We came here and did our jobs. Why can’t other guys come and do their jobs, too?”

Velez eyed a dusty Kut street for snipers, then sighed that he was leaving it to his wife to break the sad news to his daughter, 3, and son, 8. “To me it’s like breaking his heart, and breaking my heart. So I’m going to let my wife do it. I gotta stay focused.”