BANGKOK, OCT. 20 -- The military government of Myanmar, formerly Burma, today banned most of the country's Buddhist organizations, which have become an active source of opposition to martial law.

State radio, monitored in Bangkok, said all but nine Buddhist groups would be banned as of Sunday.

"These illegal organizations through their deeds, words and publications are threatening, blackmailing and boycotting the state government and are found to be undermining law and order," the radio said late Friday.

"They are found to be engaged in political activities which do not befit the Buddhist religion," it said.

Monks, deeply revered by Burmese and seen as political leaders in times of crisis, have spearheaded opposition to the military government since it refused to recognize a landslide election victory by its opponents in May.

Monks in Mandalay and other northern Burmese towns have boycotted army officers and their families since Aug. 27, refusing to perform religious services.

The military killed more than 1,000 civilians in 1988 when it crushed a nationwide uprising. The army council said Thursday that the boycott had spread to the capital, Yangon (formerly Rangoon), and warned monks to end it by Saturday.

"I have tolerated as much as I can and you, my teachers, can see that I have also been doing whatever is necessary. I have decided to take measures that should be taken," army chief Gen. Saw Maung was quoted as telling a meeting of spiritual leaders.

The monks have joined with the opposition winners of the May elections in challenging the army to keep its promise to hand over power to an elected civilian government. The National League for Democracy, which won more than 80 percent of the seats in the election, has been banned from forming a government.

Two of its leaders from Mandalay, Ohn Gyaing and Thein Dan, were jailed this week for seven years for handing out army pamphlets. Its acting chairman and secretary are in detention.