Myanmar is on the verge of freeing political prisoners, officials said Monday, as the United States hailed "dramatic developments" in the country after decades of military rule. The release of the country's estimated 2,000 political detainees, who include pro-democracy campaigners, journalists and lawyers, has long been a top demand of Western nations which imposed sanctions on Myanmar. "Political prisoners will be released. But we still do not know whether all of them will be freed," said a government official who did not want to be named, adding that the pardon was expected "within days". A second official said the release would come before President Thein Sein leaves Wednesday on an official visit to India. An amnesty would be the latest sign of political change under a new nominally civilian government that has reached out to critics including opposition leader Aung San Suu Kyi, freed in November after seven straight years of detention. Her National League for Democracy (NLD) said it was "expecting" all political detainees to be released. A top US official, Kurt Campbell, on Monday hailed recent developments in Myanmar, including what he described as "very consequential dialogue" between Suu Kyi and the leadership. Campbell, one of several US officials to hold rare talks with Myanmar Foreign Minister Wunna Maung Lwin in Washington recently, said while concerns remain, "it is also undeniably the case that there are dramatic developments under way". US President Barack Obama's administration has pursued both diplomatic engagement towards and continued sanctions against Myanmar. But it has maintained sanctions amid continuing concern over political prisoners and human rights abuses in conflicts with armed ethnic minority rebels. "We have made clear our desire to see continued progress on issues such as prisoner releases," Campbell, the US Assistant Secretary of State for East Asian and Pacific Affairs, said at a Bangkok lecture. He hinted that concrete moves towards democracy by Myanmar could lead to an easing of sanctions. "We will match their steps with comparable steps," he added. The new regime, which came to power after controversial elections held a few days before Suu Kyi's release, appears keen to improve its international image and in August held the first talks between her and Thein Sein, a former general. In a rare concession to public opinion in the authoritarian nation, the government last month suspended construction of a controversial mega-dam, risking the anger of traditional ally China which is backing the project. Suu Kyi, whose party won 1990 elections by a landslide but was never allowed to take power, has said she believes Thein Sein genuinely wants to push through reforms, but she cautioned it was too soon to say whether he would succeed. The NLD boycotted last year's ballot, largely because of rules that would have forced it to expel imprisoned members. As a result it was delisted as a political party by the regime. NLD spokesman Nyan Win said he was optimistic that hundreds of the party's imprisoned members would be freed. "We are expecting the release of all political prisoners," including student activists, he said. Myanmar's foreign minister held talks Monday with Chinese leaders to try to ease Beijing's concerns over the halting of the $3.6 billion Myitsone Dam project. Wunna Maung Lwin told Chinese Vice President Xi Jinping in Beijing that Myanmar "cherishes friendly relations with China" and attaches "great importance" to its concerns over the dam issue, Chinese state media said. Chinese foreign ministry spokesman Liu Weimin told reporters the two neighbours had agreed "to handle this project in the proper way and continue to move forward with bilateral relations, which are very important to us".