BURMA said yesterday that it had taken "pre-emptive measures" against activists of the opposition National League for Democracy (NLD) to ensure, "peace and tranquility".
In a statement released in Bangkok, the Burmese embassy denied there had been any arrests but said "some invitees" to an opposition congress in the capital, Rangoon, "were called by the authorities for questioning".
It gave no indication of the number of people involved.
The statement said the congress, which 600 persons were expected to attend, was scheduled without official permission and risked triggering disturbances which could destabilise the country.
"The government, therefore, was compelled to take preemptive action today [Friday] to forestall the meeting. There were no arrests. Some invitees to the congress were called by the authorities for questioning."
It was the second time this year the junta had moved to thwart NLD plans for a major party meeting. In May, more than 260 activists were detained ahead of a planned nationwide congress.
Early yesterday morning an unknown number of NLD activists were picked up at their homes in Rangoon and taken for questioning, opposition sources said.
From midnight on Thursday, security forces, including armed riot police, blocked off access to the home of NLD leader, Ms Aung San Suu Kyi, where the party meeting was to have taken place.
A second blockade was thrown up at noon around the NLD's Rangoon division office where some 150-200 party activists had gone after being turned away from the meeting venue.
The statement, which noted that news agencies and embassies had been invited to attend the three-day meeting starting yesterday, said: "The NLD did not seek permission to hold the mass meeting although the rules and regulations prescribe to get the prior permission of the authorities of the area concerned.
"At the congress the NLD planned to read papers on politics, economics, law and youth affairs and decided to issue declarations which will contain demands."
It said that, because the congress coincided with the UN General Assembly session and with a new US law on Burma, "there could arise undesirable disturbances following internal political confusion, resulting in destabilisation of the country".
The statement also accused the NLD of repeatedly discussing preparations for the congress with "the Head of Mission and other officials from an embassy in Yangon". It did not identify the embassy, but observers believed it to be that of the United States.
. Britain yesterday deplored the detention of more than 100 pro-democracy activists in Burma and said it was consulting with its European Union partners about possible measures against the Rangoon government.
"We deplore the latest detention of members of the National League for Democracy," the ministry said in a statement. "It is a clear obstruction of a legal political party."