YANGON (Reuters) - Myanmar's outgoing President Thein Sein has at the last minute canceled plans to attend the U.S.-ASEAN summit in California next week, his office said late on Thursday, giving no reasons for the decision.
While no official delegation from the Myanmar side had been announced before, experts expected the trip to be Thein Sein's last chance to highlight his reformist legacy in front of President Barack Obama and Southeast Asian leaders.
Thein Sein's Union Solidarity and Development Party was crushed by Aung San Suu Kyi's National League for Democracy in a November election, kicking off a lengthy transition process that will end on April 1 when the new government's term begins.
"Vice president Nyan Htun will visit the United States on behalf of president Thein Sein," an announcement by the President's Office read.
"President Thein Sein is not visiting the U.S. because he has other business to attend to, that's all we can say," said Zaw Htay, a senior official at the President's Office contacted by phone.
Myanmar's military, which is guaranteed 25 percent of seats in parliament and three security ministries under the constitution, is negotiating the terms of the transition with Suu Kyi. Details of those talks remain murky.
Thein Sein's decision will likely intensify already frantic speculation over the state of behind-the-scenes negotiations in Myanmar's capital, Naypyaitaw.
The parliament decided on Monday to begin its election process for the new president on March 17, pushing back the NLD's original plans by about three weeks and suggesting talks between the party and the military have hit a snag.
In 2011, Thein Sein's semi-civilian government replaced a military regime that had ruled Myanmar for 49 years, ushering in political and economic reforms. International observers lauded Thein Sein for organizing credible elections.
Leaders from the Association of Southeast Asian Nations will meet Obama at a summit in the Californian resort of Sunnylands on Feb. 15-16.
(Reporting by Hnin Yadana Zaw; Writing by Antoni Slodkowski; Editing by Ruth Pitchford)