Updated

Allied forces have captured a half brother of Saddam Hussein in northern Iraq, a U.S. official said Sunday.

Watban Ibrahim Hassan, who had in the past served as an adviser to his half brother, was captured near Mosul as he apparently tried to flee to Syria, the official said, speaking on condition of anonymity.

Hassan had fallen out of favor with Saddam in 1995 and was dismissed as Iraq's interior minister, head of the regime's secret police and other domestic security agencies.

Saddam viewed Hassan as a threat and kept a close watch on him, the official said. Saddam's son Odai is reported to have shot Hassan around the time of his dismissal as interior minister.

Defense Secretary Donald H. Rumsfeld said Sunday that several top Iraqi officials had made it to Syria, with some remaining there and others moving on to different countries.

He declined to identify the Iraqis or the other countries, or if the United States was prepared to take any punitive action against Syria.

"We certainly are hopeful Syria will not become a haven for war criminals or terrorists," Rumsfeld said.

Busloads of Syrians have entered Iraq to fight against the U.S.-led coalition, Rumsfeld said. Some of them have been turned back to Syria, others have been captured and still others have been killed in firefights, he said.

U.S. troops captured one bus filled with Syrians as well as several hundred thousand dollars in cash and "leaflets suggesting that people would be rewarded for killing Americans," Rumsfeld said on CBS' Face the Nation.

Syria's deputy ambassador to the United States, Imad Moustapha, who appeared after Rumsfeld on NBC's Meet the Press, denied that his country was harboring escaped Iraqis. He said it was the responsibility of U.S. troops to monitor Iraq's western border with Syria.

Rumsfeld said he did not have solid evidence about the fate of Iraqi President Saddam Hussein, but "that regime is history forever... He either is dead or he is going to be caught; we'll find him, the world will find him."

Pockets of resistance as well as Fedayeen Saddam "death squads" remain in Iraq, Rumsfeld said.

"The war isn't over. There are still people being killed. We lost some people last night," Rumsfeld said on CBS.

On Saturday, Vice Adm. Timothy Keating, the commander of all naval forces in the war, said two or three of the five U.S. aircraft carriers launching planes on missions over Iraq may head home soon. Each carrier has about 80 planes aboard, including about 50 strike aircraft.

While the air campaign is far from over, its focus has shifted away from heavy bombing toward protective air cover for ground troops around Baghdad and in northern Iraq.

Surveillance and reconnaissance missions by U-2 spy planes, unmanned Predator drones and other aircraft are continuing apace, and aerial refueling and cargo planes are still very busy.

Keating said the USS Kitty Hawk, which has operated in the Persian Gulf since February, probably would be the first to leave. Its home port is Yokosuka, Japan.

The USS Constellation, also in the Gulf and on its final active deployment, probably would go next, he said.

Keating said orders to send carriers and other forces home would have to come from Gen. Tommy Franks, the war's overall commander, and that no such orders have been received.