Myanmar opposition leader Aung San Suu Kyi and 42 others refused to take their seats in Parliament Monday, saying the wording of their oath must be changed. The members of the National League for Democracy party said they want the wording of the swearing-in oath changed to say members of Parliament will \"abide by\" the constitution rather than \"protect\" it, CNN reported. \"We want to change that constitution because it\'s not a democratic constitution,\" said Ohn Kyaing, a spokesman for the NLD. Under the constitution, 25 percent of the 664 seats in Parliament go to unelected members of the military establishment. PHOTOS: Sen. Jim Webb meets Myanmar leaders CNN said the dispute over the wording of the oath marked the first indication of tension between the opposition and the reformist government of President Thein Sein since the NLD won seats in April 1 special elections. Western governments had pointed to the elections and other reforms as signs the country was making progress in its move toward democracy after decades of military rule. Tin Oo, a senior NLD official, said the president had agreed before the elections to amend the oath. \"Whether Ms. Aung San Suu Kyi enters Parliament or not is her decision,\" the president said Monday. \"She has to decide it. The Parliament is all in favor of her entrance and very welcoming of her.\" In the past year, the Myanmar government has pardoned hundreds of political prisoners, entered a cease-fire with Karen rebels and agreed to negotiate with other ethnic rebel groups, CNN said.