19 March, 2008 - Published 18:57 GMT
The United Nations special envoy to Burma, Ibrahim Gambari, says there have been no tangible results from his recent visit.
After briefing the Security Council, Mr Gambari said the trip had been difficult and frustrating; he said efforts would continue, but there would be no progress in improving Burma's relations with the international community unless the military government released the opposition leader, Aung San Suu Kyi.
The government plans a referendum on a new constitution, followed by elections, but intends to reserve many powers for itself.
UN's role to continue
Mr Gambari said the opposition leader Daw Aung San Suu Kyi still wants the UN to be involved in bringing substantive political talks in Burma.
U Nyan Win, the spokesperson of the National League for Democracy, said the NLD welcomes UN's continued involvement.