(Adds quotes) By Matt Spetalnick WASHINGTON, Aug 9 (Reuters) - U.S. President George W. Bush insisted on Thursday that Iran is a destabilizing force in Iraq despite Tehran's assertion to Iraqi Prime Minister Nuri al-Maliki that it is helping secure his country. Calling Iran a "very troubling nation" that must be isolated, Bush warned during a White House news conference: "When we catch you playing a nonconstructive role (in Iraq), there will be a price to pay." Bush spoke as Maliki, facing deepening political woes at home and U.S. criticism for lack of progress in bridging sectarian divisions, won pledges of support from Shi'ite Iran during a visit to the neighboring country. Playing down signs of warming ties between Baghdad and Tehran, Bush -- struggling to rally U.S. public support for the unpopular Iraq war -- voiced confidence that he and Maliki see eye-to-eye on Iran as a threat. "If the signal (from Maliki) is that Iran is constructive, I will have to have a heart-to-heart with my friend, the prime minister. Because I don't believe they are constructive," Bush said. "I don't think he, in his heart of heart(s), thinks they're constructive either." He suggested Maliki had been photographed smiling with his Iranian hosts, including U.S. foe President Mahmoud Ahmadinejad, only as a diplomatic nicety. "You don't want the picture to be kind of, you know, duking it out," Bush said, holding up his fists like a boxer. It was the second time this week Bush has had to defend his tough stance against Iran with cautionary words to a key ally in the face of possible differences over Tehran's motives. He warned Afghan President Hamid Karzai on Monday during a visit to the U.S. presidential retreat at Camp David to be more suspicious of Iran after the Afghan leader had brushed aside U.S. accusations that Tehran was arming the Taliban. Iran, with a majority of Shi'ite Muslims like Iraq, has been an important political player in Iraq since the 2003 U.S.-led invasion. Tehran denies Washington's accusations that it is supplying weapons to militants to fuel violence, and instead blames the U.S. military presence. Baghdad has urged both countries to negotiate and not fight out their differences on Iraqi soil. IRAN PLEDGES SUPPORT TO MALIKI During Maliki's visit, Iran's First Vice President Parviz Davoudi told him Tehran "has always made a special effort to help provide and strengthen security in Iraq," the official IRNA news agency reported. But Bush dismissed the idea that Iran had a positive role in Iraq, where violence between majority Shi'ites and minority Sunnis has seemed at times to verge on civil war. That has fueled demands from Democrats who control the U.S. Congress for a timetable for U.S. withdrawal, something Bush has rejected. Little more than a month before the Sept. 15 deadline for a crucial Iraq progress report, Bush urged lawmakers to move quickly after their August recess to pass new war funding. Bush said Maliki "knows that weaponry being smuggled in to Iraq from Iran and placed into the hands of extremists -- over which the government has no control, all aimed at killing innocent life -- is a destabilizing factor." He said he had asked U.S. diplomats to hold recent meetings with Iranian officials in Baghdad to "send a message that there will be consequences" for arms smuggling into Iraq. His message to the Iranian people was, "You can do better than this current government." Iran this week said Washington wants to topple its leaders with a "soft revolution." Bush reiterated Western accusations that Iran's uranium enrichment program is aimed at creating nuclear weapons and called it "very dangerous for world stability." Tehran insists its nuclear program is solely aimed at producing electricity. The U.N. Security Council has imposed two rounds of sanctions since December on Iran for failing to halt uranium enrichment. A third sanctions resolution is being considered. (Additional reporting by Jeremy Pelofsky)
