'If this continues unaddressed, further bloody confrontation is unavoidable,' he told a hearing of the US Commission on International Religious Freedom, a non-partisan panel appointed by the US president and leaders of Congress.
'The very existence of monastic life is being destroyed by the evil military regime and it will face bloodshed again, if the international community, including the UN Security Council, cannot find a collective and effective way to stop this evil regime from killings and arrests,' he said.
At least 15 people died and 3,000 were jailed when Myanmar's military and police broke up pro-democracy protests, which saw Buddhist monks lead 100,000 people in the streets of Yangon on successive days.
Nayaka, a visiting scholar at Columbia University, said he had been working closely with U Gambira, the leader of the Alliance of All Burma Buddhist Monks and key leader of the September protests arrested by the junta last month.
He expressed regret that pressure by the international community on the junta had eased even as serious questions remained over the number of monks forcible disrobed, imprisoned and killed following the protests.
'Where has the global outcry gone? This should be of grave concern for all governments worldwide. This is a moral crisis that Americans must stand for,' he said.
The United States, which has long imposed a trade and investment ban on Myanmar, has twice tightened sanctions since the clampdown on protests.
It ordered an asset freeze on key junta figures and blacklisted seven companies and five individuals allegedly linked to those companies and the regime.
Aung Din, executive director of the US Campaign for Burma, urged Washington to appoint a full-time sanctions coordinator for Myanmar as it did in the late 1990's against Serbian leader Slobodan Milosevic's regime accused of genocide.
This would enable coordination of global sanctions against Myanmar's junta, he said.
Citing the Australian government which had targeted financial sanctions against 418 Myanmar citizens, including 40 businessmen, he asked the US government to impose restrictions on more Myanmar businessmen who provided money to the junta leaders and their families.
Jared Genser, president of human rights group Freedom House, raised the prospect of Washington imposing sanctions, such as those used against a Macau bank accused of money laundering for nuclear-armed North Korea, on a Southeast Asian state-owned bank suspected of links to Myanmar's military rulers.
The move against Baco Delta Asia in Macau underscored US financial clout and reportedly compelled North Korea back to the negotiating table.
'Anecdotally in conversations with diplomats in Asean countries, I know there is a deep concern about the prospects of the United States doing to a state-owned bank what happened to Banco Delta Asia in Macau because of its laundering of North Korean funds,' Mr Genser told the hearing.
He did not name the bank.
The Association of Southeast Asian Nations comprises Brunei, Cambodia, Indonesia, Laos, Malaysia, Myanmar, the Philippines, Singapore, Thailand and Vietnam. -- AFP