The South Korean National Assembly voted tonight to set up a constitution revision committee, a move the government and opposition moderates hope will defuse a political crisis that has been gaining steam on South Korean streets since February.

It remains unclear whether the committee will be able to draft amendments acceptable to both sides. But its formation marks a major concession by President Chun Doo Hwan, who until recently had maintained that changing the constitution was out of the question.

A resolution for creation of the committee passed late tonight in the assembly, which is controlled by Chun's Democratic Justice Party. The vote followed a meeting Saturday between Chun and opposition leaders in which basics of the committee were agreed upon.

Plans call for the panel to draw up, before the next regular session of the assembly ends Dec. 18, a compromise bill amending the constitution. The bill would then be put to a vote before the assembly.

The crisis began in February when the assembly's main opposition group, the New Korea Democratic Party, opened a petition campaign to press for a constitutional amendment to require the direct election of the president. The party contends that the current electoral college system is open to manipulation by the government.

Chun initially responded with a wave of arrests but then switched course and agreed that the campaign could proceed. The opposition subsequently held large rallies and marches in nine cities. Many of the gatherings broke down at the end into street battles between demonstrators and police. Nearly a million people were said to have signed the petitions.

On university campuses, radical students staged hundreds of protests. Three students set themselves on fire, and two police officers were reported to have died of injuries suffered in clashes with students.

With church groups taking the opposition's side and criticism being heard from abroad, the government in April took a new tack again, saying that amendment of the constitution was possible if the assembly approved.

In negotiations ahead, opposition groups are expected to argue for the creation of a system with direct elections. People in Chun's government, however, have been talking of a cabinet form of government without direct elections.

Another potential area for conflict is composition of the committee and political prisoners.

The opposition party has called on the government to release all political detainees as a sign of good faith. The government says it has let out 200 people viewed by the opposition as political prisoners and will make efforts for clemency for another 800 or so still detained.

It is unclear whether formation of the committee will reduce protests by students on the far left, many of whom have accused the New Korea Democratic Party of selling out to the government. But the government apparently hopes that the move will isolate them from mainstream opponents.

In a separate development, the U.S.-led United Nations Command in Seoul today rejected a North Korean proposal for three-way defense talks between Pyongyang, Seoul and the U.N. Command, saying there were already proper forums for such discussions.