YANGON (Reuters) - U.N. Secretary-General Ban Ki-moon made a landmark visit to a fast-changing Myanmar on Sunday to encourage its government to carry out more democratic reforms and shore-up peace deals with ethnic rebel groups.
Ban's trip was his first since a reformist, quasi-civilian government took office a year ago, ending five decades of authoritarian military rule and frosty and frustrating ties with the international community.
His trip coincides with a visit by EU Foreign Policy chief Catherine Ashton to open a "new chapter" of relations as European firms seek a share of Myanmar's vast untapped natural resources.
Myanmar, which is still led by remnants of the former junta, has stunned the outside world with economic reforms and unprecedented engagement with the West, the political opposition and ethnic minority rebel groups, moves Ban said were encouraging, but still not enough.
"We see Myanmar is reopening to the world," he said earlier in New York, adding that "the fresh start is still fragile".
A string of Western politicians, including U.S. Secretary of State Hillary Clinton and British Prime Minister David Cameron, have travelled to Myanmar in recent months to encourage it to stay on the path of reform.
Ban arrived in the commercial capital Yangon and will see a country that has undergone astonishing changes since his last visit in July 2009 on the invitation of former junta strongman Senior General Than Shwe, which was widely seen as a stunt to boost the regime's credibility at home.
Ban left frustrated, describing it as a "very difficult mission" having failed to convince Than Shwe to release political prisoners and being denied access to Nobel Peace Prize laureate Aung San Suu Kyi, who was in detention at the time but was released 15 months later.
Since Than Shwe stepped aside on March 30 last year, four months after an election seen as rigged, its former fourth-in-command Thein Sein has become president and has brought Suu Kyi into the political fold.
His government has started overhauling the tattered economy, easing media censorship, legalising trade unions and protests, freeing political prisoners and agreeing ceasefires with more than a dozen ethnic rebel armies.
Thein Sein is planning to restructure negotiating teams after a failure to make a breakthrough in six rounds of talks with Kachin rebels and their political leaders, two sources close to the peace effort told Reuters.
Ban was due on Monday meet Thein Sein and other former generals who were part of Than Shwe's inner circle but now seen as key drivers behind Myanmar's stunning facelift, which has led to an easing of some sanctions this month by the European Union, United States, Australia and Canada and a resumption of aid and debt relief by Japan.
Ban was scheduled to fly to the remote capital Naypyitaw later Sunday. His visit will include a trip to northern Shan State, one of the world's biggest opium-growing regions, where the United Nations has started poppy eradication programme it says has seen significant progress.
Ban is also due to discuss a census the United Nations is helping Myanmar to compile by 2014, its first in over 30 years and is scheduled to give an address to Myanmar's huge new parliament on Monday, the first by a foreigner.
Suu Kyi's National League for Democracy party was due to make its debut in parliament last week after an historic by-April 1 by-election win, but it is still refusing to take its seat because of a potentially troublesome dispute over the wording of a swearing-in oath.
Additional reporting by Louis Charbonneau at the United Nations; Editing by Nick Macfie