ARNOLD, Md. – President Bush yesterday demanded in blunt terms that Syria get out of Lebanon, saying the free world is in agreement that Damascus’s authority over the political affairs of its neighbor must end now.

He applauded the strong message sent to Syria when Secretary of State Rice and the French foreign minister, Michel Barnier, held a joint news conference in London on Tuesday.

“Both of them stood up and said loud and clear to Syria, ‘You get your troops and your secret services out of Lebanon so that good democracy has a chance to flourish,'” Mr. Bush said during an appearance at a community college in Maryland to tout his job-training programs.

The world, Mr. Bush said, “is speaking with one voice when it comes to making sure that democracy has a chance to flourish in Lebanon.”

The president’s words, taken with those from Ms. Rice and others in the Bush administration this week, amount to the strongest pressure to date on Syria from Washington.

“Syria knows the concerns of the international community, and they know what they need to do to change their behavior and become a constructive member of the region and the international community,” White House press secretary Scott McClellan said earlier yesterday.

Turkish ambassador Osman Faruk Logoglu urged the Bush administration to offer trade and other economic and diplomatic incentives to Syria.

“The chances of Syria withdrawing are greater than ever before,” Mr. Logoglu told reporters. “But it is obviously going to take a long time.”

Ms. Rice, in London to attend an international conference on Palestinian Arab security and government reform, had said Tuesday that Syria is “out of step” with a growing desire for democracy in the Middle East.

The Bush administration also on Tuesday blamed terrorists based in Syria for last week’s deadly suicide attack in Israel.

Mr. McClellan said the White House has “firm evidence” that Syria was the home base for the terrorist attack in Israel that rocked the latest efforts for peace between Israel and the Palestinian Arabs. Mr. Bush made a similar point during a White House meeting with congressional leaders, participants said, and so did Ms. Rice while in London.

Yesterday, Ms. Rice returned to Washington and had lunch at the White House and an Oval Office meeting with Mr. Bush, Mr. McClellan said.

All key Lebanese political decisions are assumed to have a stamp of approval from the government of President Assad.

Huge street demonstrations and Monday’s resignation of the pro-Syrian Lebanese government marked the most serious challenge to Syrian authority in Lebanon since the end of the civil war that killed 150,000 and crushed the Lebanese economy in the 1970s and 1980s.

The events also were an opening for the Bush administration to press its wider goal of democracy across the Middle East and to throw a spotlight on what America contends is long-standing Syrian support for terrorists who are trying to undermine progress toward Israeli-Palestinian peace.

At the news conference with Mr. Barnier, Ms. Rice said their two countries would support the scheduled election this spring in Lebanon, perhaps by sending observers and monitors.

She also suggested international peacekeepers might be needed eventually and could help secure democracy for the Lebanese if Syria were to withdraw.

Mr. Assad indicated in an interview with Time magazine that he would withdraw Syria’s 15,000 troops from Lebanon “maybe in the next few months.” Later, however, a Syrian official speaking on condition of anonymity in Damascus questioned whether it could occur within months.

The U.S. deputy assistant secretary of state, David Satterfield, on Capitol Hill after a trip to Lebanon, was dismissive of what he called the “rhetoric” out of Damascus.

“Neither this government nor the people of Lebanon will believe anything other than what we see with our eyes,” Mr. Satterfield told the Senate Foreign Relations Committee.

Separately, on the issue of Iran’s nuclear program, Ms. Rice indicated that the administration was working with European leaders on a plan to offer Iran economic incentives in exchange for abandoning its nuclear ambitions. America has accused Iran of developing nuclear weapons, a charge Tehran denies.

“We are designing, I think, an important common strategy with Europe so that Iran knows there is no other way,” Ms. Rice said in a brief interview aired yesterday on NBC’s “Today” show.

Until recently, the administration had opposed any rewards for Tehran’s cooperation. But during the president’s trip overseas last week, European leaders urged Mr. Bush to join them in offering incentives such as possible membership at some time for Iran in the World Trade Organization and the White House suggested he would consider that route.