Updated

The top Republican on the Senate Armed Services committee said Wednesday he wants Defense Secretary Donald H. Rumsfeld to appear before the panel to discuss how prepared U.S. forces are for a war against Iraq.

Sen. John Warner of Virginia is the latest GOP lawmaker to insist that Congress be heard in the debate on whether to invade Iraq -- even as the Bush administration says that congressional authorization isn't legally required.

"Congress, as a co-equal branch of government, is, in my opinion, not going to sit on the sidelines," Warner said in a letter to committee chairman Sen. Carl Levin, D-Mich. The letter was dated Tuesday and released Wednesday.

Despite the determination of White House lawyers that Bush does not congressional approval, President Bush's advisers have concluded that it would be prudent to seek some sort of expression of support from lawmakers if Bush decides on military action.

Intense debate also is under way within the administration on whether to seek a U.N. Security Council vote declaring that Iraqi President Saddam Hussein must readmit weapons inspectors.

Warner said the time has come for the committee to hold hearings on Iraq after the congressional recess ends next week. He said the first witnesses should be administration officials -- preferably Rumsfeld and Joint Chiefs of Staff Chairman Gen. Richard Myers.

In a statement Wednesday, Levin said he has been considering holding hearings on Iraq and would decision after the recess.

Pentagon spokeswoman Victoria Clarke said Rumsfeld expects to be asked to testify next month and is prepared to do so.

Speaking in Crawford, Texas, where Bush is vacationing, White House spokesman Scott McClellan said hearings would be "part of a healthy discussion about how we move forward on Iraq."

Warner said "there appears to be a 'gap' in the facts possessed by the executive branch and the facts possessed by the legislative branch."

In an interview, Warner said his reference to the gap wasn't meant to criticize the administration, but to acknowledge that administration officials are constantly gathering intelligence, making assessments and conferring with foreign leaders.

Warner noted that "the crescendo of this debate [on Iraq] has risen dramatically in the last two weeks."

During that time, leading Republicans from past administrations have expressed reservations about an attack. On Monday, Vice President Dick Cheney offered a point-by-point rebuttal, saying the United States could face devastating consequences if Saddam stays in power and develops chemical, biological and nuclear weapons.

U.S. allies have increasingly urged the United States against an attack. On Wednesday, a senior Turkish diplomat cautioned that an attack could lead to the breakup of Iraq. Turkey serves as the base for U.S. and British surveillance flights over Iraq.

In Washington, Foreign Ministry Undersecretary Ugur Ziyal spoke with Secretary of State Colin Powell, Deputy Defense Secretary Paul Wolfowitz, and Condoleezza Rice, the president's national security adviser. Ziyal also spoke via video conference with Vice President Dick Cheney.

Speaking separately at the Washington Institute for Near East Policy, Ziyal urged a tightening of world sanctions against Iraq.

Asked about widespread opposition to military action against Iraq, State Department spokesman Richard Boucher reaffirmed that Bush has not yet made a decision.

"The president made clear we'll continue to talk to other governments and consult with them, hear their views, as he decides how to go forward," Boucher said.

The White House announced this week that if it decides to invade Iraq, it's not legally bound to seek Congress' authorization. Bush spokesman Ari Fleischer said the president hasn't ruled out seeking their approval.

Many lawmakers have urged Bush to do so, including Republicans Rep. Henry Hyde of Illinois, the chairman of the House International Relations Committee, and Sen. Chuck Hagel of Nebraska, a Foreign Relations Committee member.

Warner said he agreed with the White House that formal congressional permission may not be needed before an attack.

But he also stressed the work of the Armed Services Committee in the debate leading up to the 1991 Persian Gulf War -- and his own efforts to win a congressional resolution authorizing the use of force then.

"Congress has to be a partner, not necessarily in deciding when to act, but to support the president," said Warner, a former secretary of the Navy. He said the Armed Services Committee won't seek details on battle plans, but would want information on issues such as U.S. weapons stockpiles and force readiness.

Shortly before the recess, the Senate Foreign Relations Committee held two days of hearings on Iraq, with analysts discussing whether an attack was needed and possible consequences.

The House International Relations Committee is also expected to hold hearings after Congress returns.