Aung San Suu Kyi, Myanmar's detained democracy leader, has refused to meet with Ibrahim Gambari, the visiting UN envoy, state television said.
Gambari flew to Yangon hoping to revive talks between the Nobel Peace Prize winner and the military government, but he was shunned by her and by the military's senior leadership.
Aung San Suu Kyi ignored pleas by two of Gambari's aides for her to speak with him, state TV said on Saturday.
It showed images of the pair waiting outside the gate to her house, where she has been confined for most of the last 19 years.
The broadcast also showed Myanmar officials shouting into a megaphone, saying, "Mr. Gambari wants to meet you."
Gambari did meet Thein Sein, the prime minister, after he extended his trip by a day.
But Thein Sein is not a senior member of the government and has little influence over decision making.
"It's a failure. The prime minister is not a powerful person who can make a decision to revive the talks. The worst thing is not being able to see Aung San Suu Kyi," Win Min, a Thailand-based Myanmar analyst, said.
"For Gambari, this time he will be very disappointed... I think it will be very difficult for him to continue the mission," Win Min said.
"Last time she met him but there has been no progress since then....She won't want to be used for Gambari to say his mission is working."
Gambari had initially made some progress in the wake of Myanmar's deadly crackdown on pro-democracy protests led by Buddhist monks last September.
Seeking to soothe international outrage at the bloodshed, the generals appointed a liaison to meet with Aung San Suu Kyi.
But the two have not met since January, when the opposition leader complained about the slow pace of their talks.
On Gambari's last visit in March, the military openly rebuffed all of his calls for political reform and Than Shwe, the the military's leader, refused to see him.
Aung San Suu Kyi's apparent rejection of Gambari's mediation highlights the political stalemate in Myanmar, which has been ruled by the military since 1962.
Her National League for Democracy (NLD) won a landslide in 1990 elections, but was never allowed to govern.
The military instead unveiled its own "road map" to democracy, and after more than a decade of delays, has drafted a new constitution that was approved in a referendum in May. The charter is expected to set the stage for new polls in 2010.
But the NLD has derided the process as meaningless, accusing the military of rigging its 92 per cent victory in the referendum. It wants the generals to open talks with Aung San Suu Kyi and the country's many ethnic minorities.