Nov 27, 2007 (AP), A UN human rights investigator who recently returned from Burma said he believes there are more political prisoners detained in the country than the government says, although he would not estimate how many.

Paulo Sergio Pinheiro visited Burma for five days this month to look into allegations of abuse by the ruling military junta and to determine how many people were killed or detained in the September crackdown on a series of pro-democracy protests led by Buddhist monks.

Security forces killed at least 15 people and detained nearly 3,000 protesters, according to information Burmese authorities provided to Pinheiro. Diplomats and dissidents say the death toll was much higher.

The regime has said it has since released most of the detainees, but Pinheiro said Tuesday that the government’s claim that only 93 people remain in detention is most likely not true.

"I don’t think this number corresponds to reality," Pinheiro told an audience at Brown University’s Watson Institute for International Studies, where he is a visiting professor. "Ninety three is too low. I think it’s a larger number of people continuing in detention."

He declined to provide his own tally and said he expects to give a more detailed report to the UN Human Rights Council in Geneva next month.

Pinheiro has said at least 15 people died in Rangoon, Burma’s largest city, a number based on post-mortem reports and other official information. He has said he was continuing to investigate the overall number of deaths and did not provide an updated count on Tuesday.

He said in an interview after his speech that he was still looking into whether monks were among those killed.

Images of peaceful demonstrations being met with violence sparked "universal revulsion" and that the international community has the opportunity to seize on that outrage and create positive change, Pinheiro told The Associated Press after his talk.

"The attention of the concerned countries is very short," he said. "My fear is that all the scenes of these marches, these demonstrations, will soon be forgotten, and then we will lose an opportunity."

He said the crisis in Burma required "quiet diplomacy" as well as support and coordination from other countries.

"The international community has to prove some effectiveness, some competence