Burma's military government has rejected a U.N. proposal to allow independent observers at its constitutional referendum planned for May.
U.N. envoy Ibrahim Gambari had proposed the idea of election observers during his meetings with government and opposition leaders this week.
Gambari met Saturday with pro-democracy leader Aung San Suu Kyi and senior leaders of her National League for Democracy party.
The Nobel Peace laureate was seen being driven from her Rangoon home, where she has been held under house arrest for 12 of the last 18 years. She was taken to the nearby State Guesthouse, where Gambari has held most of his meetings since arriving Thursday.
Burma's military rulers have refused to amend a draft constitution that bars Aung San Suu Kyi from public office.
The draft constitution prohibits anyone married to a foreigner from running for public office. Aung San Suu Kyi was married to a British citizen who died of cancer in 1999.
Gambari is in Burma on a mission to persuade the military government to hold direct negotiations with her, and allow her party to participate in the country's political process.
The Nigerian diplomat's visit to Burma is his third since the military government's crackdown on pro-democracy protests last September, which the U.N. says killed more than 30 people.
Some information for this report was provided by AFP, AP and Reuters.