Aung San Suu Kyi's opposition party refused to take its new seats in parliament Monday because of a dispute over one word in the lawmakers' oath, but party officials said the issue would be overcome soon and the Southeast Asian nation's president also said a revision was possible.

The National League for Democracy party objects to phrasing in the oath that says they must "safeguard the constitution," a document they have vowed to amend because it gives inordinate power to the military and was drafted during an era of army rule. The lawmakers want the word "safeguard" replaced with "respect."

If not dealt with soon, the issue could potentially derail a fragile detente between the military-backed ruling party and Suu Kyi's opposition movement. Analysts say President Thein Sein needs the opposition in parliament to show the world that his administration is serious about change in the Southeast Asian country, which was ruled by the military for nearly half a century.

Speaking on a state visit to Tokyo, Thein Sein told reporters he was open to discuss changes to the oath. "It is possible to make a revision if it serves the public's interest," he said.

Thein Sein added that Suu Kyi was welcome in parliament, but "she is the one who should decide whether to join."

Since last year, Thein Sein's government has overseen a wave of widely praised political reforms, including the April 1 by-elections that earned Nobel Peace laureate Suu Kyi a parliamentary seat after years of repression and house arrest.

Later Monday, the European Union is expected to announce the suspension of most sanctions against Myanmar for a year while it assesses the country's progress toward democracy. The United States and other countries also have pulled back on some sanctions.

Suu Kyi and 42 other elected lawmakers from her party were absent as the latest assembly session got under way in the capital, Naypyitaw, on Monday. The party had said it would not join until the oath issue was resolved.

Opposition spokesman Nyan Win told The Associated Press that he believed the dispute would be solved within 10 days, and other party officials have said there is support within Thein Sein's government to change the oath.

The party was "not disappointed" with its current inability to sit in the assembly, Nyan Win said. "We are cooperating with the government, so the problem will be overcome."

The oath is in an appendix to the military-backed constitution, and it is unclear whether it can be changed without the approval of 75 percent of parliament. The subject was not on the agenda in Naypyitaw on Monday.

Phyo Min Thein, one of the opposition's newly elected lawmakers, said the party is pressing the issue because changing even an appendix to the constitution would be significant and highly symbolic.

"We want them to change the wording because it will show people that the 2008 constitution can be changed," he said. "That's the point."

Similar phrasing was changed in the party registration law last year, a move that opened the way for Suu Kyi's party to rejoin politics after it boycotted the 2010 vote in which Thein Sein was elected.

The constitution automatically allocates 25 percent of the parliamentary seats to unelected representatives of the military, and Suu Kyi's party maintains that is undemocratic.

The document also bars people from the nation's presidency if they or any of their relatives are foreign citizens. That effectively prevents Suu Kyi from ascending to the presidency because she is the widow of a British national, Michael Aris, and their two children were born abroad and do not live in Myanmar.

The by-election's outcome, in which the opposition won almost all of the 45 seats up for grabs, was considered a major step toward reconciliation after decades of military rule in Myanmar.

The party will have little power in the military- and ruling-party dominated legislature even when it does enter, but the overwhelming poll victory could set the stage for a major sweep during the next general vote in 2015.

"The question is whether or not the government will accept the result," Phyo Min Thein said.


Associated Press writer Mari Yamaguchi contributed to the report from Tokyo.