Iran's first official response to US President Donald Trump's surprise announcement that he is willing to meet Iran's leader "without preconditions," was posted on Twitter late Monday night."Respect for the great nation of Iran, the reduction of hostilities, and America's return to the JCPOA, will smooth the path past the current rocky relations," wrote Hamid Aboutalebi, a senior advisor to Iranian President Hassan Rouhani, referring to the 2015 nuclear accord, the Joint Comprehensive Plan of Action, by its official name.Aboutalebi, Iran's former ambassador to Australia, the European Union, Belgium and Italy, and a prominent reformist politician, set his own conditions for the meeting, though he did not reject it out of hand."A telephone conversation between the presidents of the two countries at the United Nations in 2013 was based on the firm belief that it is possible, through a commitment to dialogue, to proceed on the path of confidence building," he said of former President Obama's call with Rouhani that year. "The JCPOA is an achievement of a commitment to dialogue; this must be accepted.""Last year at the United Nations General Assembly, after threats against the great nation of Iran, the subject of a meeting between the two presidents was proposed; now, after leaving the JCPOA, a meeting without preconditions is announced! A person who believes in dialogue as a method for solving disputed in civilized societies, must also be committed to that tool," he wrote. Aboutalebi's measured response to Trump's surprise proposal testifies to the importance of sustaining the 2015 nuclear deal for Rouhani and the relatively more moderate reformist camp in Iran. A meeting between Rouhani and the American president, even if it had no immediate practical impact, would be a powerful symbolic triumph in the internal struggle between more moderate reformists and conservatives, led by Supreme Leader Ali Khamenei, over the future of the Islamic Republic. While Khamenei has rejected dialogue out of hand, reformists have advocated talks as a key to securing Iran's stability.Rouhani was first elected in 2013 on the promise of improving Iran's international standing and reviving the country's economy through an opening to the West. The 2015 nuclear agreement, negotiated between Iran and the six permanent members of the United Nations Security Council and Germany, was Rouhani's biggest success. However, the promised economic improvement has yet to materialize. After the United States withdrew from the Iran deal in May, Iran's currency, the rial, has been in free fall. International companies that had been eager to do business in Iran have pulled out of the country, fearful of becoming targets of newly-reimposed American sanctions. Iran's economic woes have sparked protests across the country over the past several months.Conservative politicians were more circumspect in their responses to Trump's announcement."If Trump had not withdrawn from (Iran's) nuclear deal (with world powers) and had not imposed sanctions on Iran, there would be no problem with negotiations with America," Ali Motahari, the conservative deputy speaker of parliament and brother-in-law of powerful conservative figure Ali Larijani, was quoted as saying by the state news agency IRNA, according to Reuters. "But negotiating with the Americans would be a humiliation now," he said.Trump's announcement followed a war of words between Tehran and Washington over the past several weeks. After President Rouhani gave a speech saying that hostile US policies would lead to "the mother of all wars," Trump warned Iranian leaders against threatening the US in an all-caps Twitter post last week.Other Iranian political leaders, including Khamenei and Iran's most powerful military leader, Revolutionary Guards commander Qassem Soleimani, responded to Trump's words, saying "if Trump starts a war, Iran will finish it."Just hours after Trump's announcement that he would meet Iran's leader without preconditions, Secretary of State Mike Pompeo listed specific conditions that Iran would have to meet in order for such a meeting to occur."If the Iranians demonstrate a commitment to make fundamental changes in how they treat their own people, reduce their malign behavior, can agree that it's worthwhile to enter into a nuclear agreement that actually prevents proliferation, then the president said he's prepared to sit down and have the conversation with them," Pompeo said in an interview on CNBC.Reuters contributed to this report.