Tue Oct 2, 12:13 AM ET

LASHIO, Myanmar - UN envoy Ibrahim Gambari was again kept waiting for a meeting with Myanmar's junta leader Than Shwe on Tuesday, as the regime said it was not to blame for a deadly crackdown on mass street protests.

Gambari, trying to see the reclusive general since the weekend to express international outrage over the bloodshed, was instead brought to a carefully orchestrated public rally in support of the government.

It was his third attempt to meet Than Shwe since arriving at the weekend, after security forces effectively stopped the protests with a crackdown that left at least 13 people dead and hundreds if not thousands behind bars.

Diplomats have warned the death toll could be far higher, as activists struggle to assess the scope of the crackdown and to find hundreds of dissidents, monks and ordinary civilians who were arrested or went missing.

The demonstrations were the biggest in two decades against the junta, which has ruled Myanmar with an iron fist for 45 years and has usually acted quickly to stifle any sign of dissent.

Speaking at the annual gathering of world leaders at the United Nations in New York, Foreign Minister Nyan Win blamed the unrest on political "opportunists" and said the junta was not responsible for the violence.

He said security forces had shown "utmost restraint" in handling the protests, which began as small-scale marches in mid-August but drew 100,000 people into the streets last week after Buddhist monks joined the movement.

"The situation would not have deteriorated had the initial protest of a small group of activists against the rise in fuel prices not been exploited by political opportunists," Nyan Win said.

He said they had been "aided and abetted by some powerful countries" and that the regime had first tried to warn demonstrators by instituting a dusk-to-dawn curfew.

"When protesters ignored their warning, they (security forces) had to take action to restore the situation," he said. "Normalcy has now returned in Myanmar."

UN Secretary General Ban Ki-moon dispatched Gambari, a Nigerian-born diplomat, to underline international concern and attempt to get the regime to ease the crackdown.

Gambari has already been allowed to meet with detained democracy leader Aung San Suu Kyi as well as senior officials, but the government has dragged its feet in arranging talks with Than Shwe in the capital, Naypyidaw.

As he waited for a hoped-for meeting on Tuesday, the envoy found himself in the city of Lashio, where Deputy Foreign Minister Kyaw Thu escorted him to a pro-government rally with tens of thousands of people in attendance.

Witnesses said many in the crowd were members of local ethnic minority groups who could not understand the speeches given in the majority Myanmar language. Some appeared to be dozing off.

"Myanmar is poised to introduce a new political system that will ensure that the next constitutionally elected government cannot be manipulated by anyone inside or outside the country," one speaker told the crowd.

Gambari stayed for about 10 minutes.

Meanwhile Japanese Deputy Foreign Minister Mitoji Yabunaka was holding talks in Naypyidaw with top military officials over the death of a Japanese journalist killed while covering the protests last week.

Yabunaka demanded the return of a video camera the journalist was carrying at the moment he was shot dead, the foreign ministry said in Tokyo.

The United States on Monday again expressed serious concerns about "continued reports of violence and intimidation" in Myanmar, where protests first erupted in August after a massive hike in fuel prices.

Rights group Amnesty International has urged the UN Security Council to impose an immediate arms embargo on Myanmar as punishment for the brutal crackdown, saying China had been the main source of weapons.