A senior Japanese official has travelled to Burma to call for the release of the opposition leader Aung San Suu Kyi.
Aung San Suu Kyi has been in detention since 30 May
Vice-Foreign Minister Tetsuo Yano met briefly with Burmese military intelligence chief, General Khin Nyunt, where he conveyed a message from the Japanese Prime Minister, Junichiro Koizumi, that Aung San Suu Kyi be set free as soon as possible.
Japan is Burma's biggest aid donor, and a Japanese Foreign Ministry spokesman has said that if the current situation continues, Japan will not be able to do business as usual with Rangoon.
UN Secretary General Kofi Annan echoed Mr Yano's call and urged the Burmese Government to release Aung San Suu Kyi immediately.
Mr Annan's spokesman, Fred Eckhard, said the secretary-general wanted the ruling junta "to acknowledge that the people of Myanmar (Burma) are overwhelmingly in favour of change".
Mr Yano's visit coincides with that of a delegation from the International Committee of the Red Cross, which is planning to meet a number of detained opposition members, but has been denied access to Aung San Suu Kyi.
The ICRC began a tour of the north of the country on Sunday to visit pro-democracy supporters rounded up in the wake of violent clashes last month which led to Aung San Suu Kyi's arrest.
ICRC official Alfredo Mallet said among those the team were expected to meet was National League for Democracy (NLD) vice chairman Tin Oo.
Rumours circulated after the 30 May clashes that Tin Oo was seriously wounded or even dead.
While the ICRC has been denied a meeting with Aung San Suu Kyi, there is no indication that Mr Yano has requested to see her.
On Friday the United States condemned Aung San Suu Kyi's continued detention, saying it had lost patience with Rangoon.
US assistant secretary of state Lorne Craner told the BBC that if the current level of outside pressure on Burma did not produce results, Washington was prepared to impose further economic sanctions.
Aung San Suu Kyi is thought to be in a two-room hut in the notorious Insein prison outside Rangoon.