US President George W. Bush and French President Nicolas Sarkozy each directed one-two punches against Iran and Syria on Saturday, telling Teheran to stop enriching uranium and scolding Damascus for backing terrorism that destabilizes the Mideast. Bush, standing with the French president at a news conference in Paris, said he was disappointed that Iranian leaders on Saturday had rejected "out of hand" a package of incentives that a group of nations, including the US and France, offered to Iran as long as it halted its uranium enrichment program. Bush said an Iran with a nuclear weapon would threaten world peace. Sarkozy chimed in, saying Iran with such a weapon would be "totally unacceptable." The French leader said the only solution was a "faultless, seamless" regime of sanctions against Iran. Assessments vary widely, but it is presumed Teheran will have enough fissile material for a weapon within a few years. A US intelligence report in December said Iran once had an active warhead program, but shelved it in 2003. But the administration argues that the continuing enrichment means the military program could be restarted at any time, and without the knowledge of the outside world. Bush also issued a warning to Syrian President Bashar Assad, saying the Syrians should stop working with Iran to destabilize the Mideast. "My message would be `Stop fooling around with the Iranians and stop harboring terrorists,"' Bush said. Both leaders were asked what message they want to send to the Syrians to get them to normalize relations with the West and achieve stability in Lebanon. In a statement issued by the French presidential palace, the United States and France sought to dispel signs that they have diverging thoughts on Syria. The joint statement called on Syria and Lebanon to quickly establish full diplomatic relations - a signal that the countries hope Damascus will reduce its interference in domestic Lebanese affairs. Bush said Syria should serve as a constructive force in the Middle East to help advance a Palestinian state and make it clear to the Islamic militant group Hamas that "their terror should stop for the sake of peace." Sarkozy warned Syria against standing with Iran on the nuclear standoff and other issues. The French president said he and Bush agreed about the need to guarantee Lebanon's independence. Sarkozy sought to play down a growing controversy about an invitation extended to Assad - among other Arab leaders - to France's Bastille Day military parade next month, and plans to include Syria in a new Union for the Mediterranean that Sarkozy has championed. The two also talked about global warming, the Middle East, trade and Afghanistan. Bush thanked France for agreeing to send at least 700 more troops to Afghanistan. They also talked about Sarkozy's new wife, model-turned-singer Carla Bruni. "She's a really smart, capable woman and I can see why you married her," Bush told Sarkozy. "I can see why she married you, too." On Iraq, Bush brushed off criticism that a long-term security deal between the United States and Iraq was faltering. "If I were a betting man, we'll reach an agreement with the Iraqis," Bush said. "Of course, we're there at their invitation. It's a sovereign nation. ... We're going to work hard to accommodate their desires. It's their country." The deal would provide a legal basis for the presence of US forces in Iraq after a UN mandate expires. Bush said the agreement would not commit future US presidents to any troop levels in Iraq and would not establish permanent US bases. Bush's upbeat assessment came as Prime Minister Nouri al-Maliki declared Friday that talks with the US on the long-term deal were deadlocked. Sunni and Shiite preachers have spoken out against enabling American troops to remain in Iraq after year's end. Al-Maliki said negotiations will continue, but his tough talk reflects Iraqi determination to win greater control of US military operations after the UN mandate expires at the end of the year. Failure to strike a deal would be a major setback for Bush ahead of the November presidential election. Bush once again predicted that a peace agreement between the Israelis and Palestinians was possible by year-end, despite setbacks and violence. "Our job is ... to keep the process moving, so I'm optimistic," Bush said. "I understand how difficult it is." Iran's rejection of the new package of incentives was expected. European Union diplomat Javier Solana presented a modified package of economic, technological and political incentives to Iranian leaders on Saturday on behalf of the United States, Germany, Britain, France, Russia and China. Iran immediately rejected the deal because it requires suspending uranium enrichment. "I'm disappointed that the leaders rejected this generous offer out of hand," Bush said. "It's an indication to the Iranian people that their leadership is willing to isolate them further. Our view is we want the Iranian people to flourish and to benefit." Bush's national security adviser, Stephen Hadley, said earlier this week that such a rejection would trigger the international community to "get much more aggressive" about enforcing the UN penalties and taking other steps to squeeze Iran's vast international business and banking relationships.