Teheran will "remove obstacles" blocking negotiations with the United States if Washington shows good will, a powerful leading rival of Iran's hard-line president said. But US President George W. Bush dismissed the possibility of talks, while accusing Iran of supplying deadly weapons to fighters in Iraq. Former Iranian President Hashemi Rafsanjani, a high-ranking cleric, has no formal foreign policy portfolio but holds seats on two of Iran's most important government bodies. Seen as one of the country's most influential figures, Rafsanjani in recent weeks has become an increasingly high-profile public advocate of a more conciliatory stance towards the US and its allies in the dispute over Teheran's nuclear program. "Any time the United States sends a signal showing good will in its dealings with Iran, we will in return remove obstacles in the way of negotiations," the official Islamic Republic News Agency quoted Rafsanjani as saying Wednesday. Bush said at a Washington news conference that bilateral talks with Iran were unlikely to yield results in the international push to halt Iran's nuclear program. "If I thought we could achieve success, I would sit down. But I don't think we can achieve success right now - and, therefore, we'll want to work with other nations," Bush said. "I think we're more likely to achieve our goals when others are involved as well." Bush accused Iran's government of sending weapons to fighters in Iraq, even if he cannot prove the orders came from the highest levels in Teheran. He said he could say "with certainty" that the weapons were provided by an elite part of Iran's Revolutionary Guards that is part of the government and said he would "do something" to protect US troops from the threat. Iranian President Mahmoud Ahmadinejad has been the most prominent voice of Iranian defiance of US and European demands that Teheran halt its uranium enrichment program. But Ahmadinejad, who defeated Rafsanjani in 2005 presidential elections, was seen as weakened by December elections in which candidates he supported were defeated or won relatively few votes. Rafsanjani, seen as a more pragmatic conservative, was strengthened by overwhelmingly winning election in December to the Assembly of Experts, which under the Iranian constitution oversees the country's Supreme Leader, Ayatollah Ali Khamenei. Rafsanjani also is head of the country's Expediency Council, which decides disputes between the elected parliament and the Guardian Council of jurists and clerics that oversee all legislation. He was appointed to the Expediency Council by Khamenei. Rafsanjani in recent weeks has said differences between Iran and the West need to be resolved through "dialogue and wisdom." It is not clear whether he is speaking for Khamenei, Iran's ultimate authority, particularly in foreign policy, or simply trying to assert his own influence over the country's complex and constantly shifting political terrain. At the same time, the former president has not shied away from strong criticism of American behavior. "The most important obstacle in the way of establishment of relations is the manner of America in seeking to dominate in dealings with other countries," IRNA quoted Rafsanjani as saying. The US and Iran broke relations in 1979 after Iranian students stormed the US Embassy in Teheran and held its occupants hostage for 444 days. Relations somewhat thawed after reformist former President Mohammad Khatami called for dialogue to bring down the "wall of mistrust," but ties worsened after Bush named Iran as part of the "the axis of evil." The United States in recent weeks also has stepped up its accusations against Teheran, claiming Iran is behind attacks against troops in Iraq, an assertion denied by Ahmadinejad.