Raising concerns about security arrangements once Saddam is out of U.S. custody, Bush said, “He’s a killer. He is a thug. He needs to be brought to trial.” Bush said it was legitimate to ask the interim government: “How are you going to make sure he stays in jail?”

Bush’s reluctance to turn over Saddam raised new questions about the extent of Iraq’s authority when the interim government claims sovereignty from the U.S.-led coalition on June 30. Bush has encountered widespread skepticism from world leaders about whether the United States truly intends to relinquish control, with 135,000 American troops remaining in Iraq to maintain security.

Asserting anew that the new government would be sovereign, Bush backed away from a U.S. confrontation with Muqtada al-Sadr, the radical Shiite cleric whose troops have led an insurgency against the U.S.-led occupation. Bush said it would be up to the Iraqi authorities to deal with al-Sadr, who has been named by U.S. officials in an arrest warrant in the assassination of a moderate rival cleric.

“When we say we transfer full sovereignty, we mean we transfer full sovereignty,” Bush said at a news conference in the Rose Garden with Afghan President Hamid Karzai. “And they will deal with him appropriately.”

In Baghdad, Iyad Allawi, the interim prime minister, had said the United States would turn over Saddam by the transfer of sovereignty. Saddam has been in U.S. custody at an undisclosed location in Iraq since his capture in December. Salem Chalabi, the Iraqi official in charge of setting up a tribunal to try former government figures, said he expected an arrest warrant filed against Saddam and other former officials before June 30.

“We have been working quite hard in the last few days on that, believe me,” Chalabi said.

Chalabi said he believed Iraqi authorities would have grounds for holding Saddam if and when he was handed over.

Bush said Saddam’s transfer would depend on “appropriate security” being in place.

“I mean, one thing obviously is that we don’t want – and I know the Iraqi interim government doesn’t want – is there to be lax security and for Saddam Hussein to somehow not stand trial for the horrendous murders and torture that he inflicted upon the Iraqi people,” Bush said.

He said he wanted to make sure that “when sovereignty is transferred, Saddam Hussein … stays in jail.”

“When we get the right answer – which I’m confident we will, we will work with them to do so – then we’ll all be satisfied,” Bush said.

In Baghdad, occupation spokesman Dan Senor suggested that U.S. authorities had grounds to hold Saddam far beyond the handover ceremony, saying the Americans could keep him “until the cessation of hostilities,” which, he said, weren’t expected to stop on June 30.

He said the U.S. goal is to put Saddam “into Iraqi hands sometime after June 30.”

White House spokesman Scott McClellan said a U.N. Security Council resolution passed last week gave the United States and its occupation partners the right to keep prisoners indefinitely.

“It provides authority for the multinational force to continue to detain individuals in Iraq after June 30 and to detain new individuals where it is necessary for security purposes,” McClellan said. He refused to say who would decide when it was “necessary for security purposes” for Americans to keep Iraqi prisoners.

“Certainly the detention policy is one of the fundamental security issues on which the multinational force and the interim government in Iraq will coordinate closely,” McClellan said.

At his news conference, Bush defended Vice President Dick Cheney’s assertion that Saddam had “long-established ties” with al-Qaida, an assertion that has been repeatedly challenged by some policy experts and lawmakers. Bush pointed to terrorist Abu Musab al-Zarqawi, who is accused of trying to disrupt the transfer of sovereignty as well as last month’s decapitation of American Nicholas Berg.