Scores of monks are trying to leave Burma's main city, Rangoon, following the military's bloody crackdown on anti-government protests, reports say.
Many monks are desperate to leave Rangoon, witnesses say
Monks were seen at the railway station and bus drivers were reportedly refusing to take them, out of fear they would not be allowed petrol.
Curfews and night-time police raids are continuing in Rangoon. Correspondents describe a climate of fear there.
A UN envoy is preparing a report on his talks with Burma's leaders.
The envoy, Ibrahim Gambari, met head of state Gen Than Shwe as well as pro-democracy leader Aung San Suu Kyi, who is under house arrest.
He is expected to brief both UN Secretary General Ban Ki-moon and the Security Council later this week.
The EU has agreed in principle to toughen already existing sanctions against Burma and is reportedly looking at ways of specifically targeting its military rulers.
Military vehicles patrolled Rangoon's streets before dawn with loudspeakers blaring: "We have photographs. We are going to make arrests."
One correspondent in Rangoon told the BBC that people in the country's former capital were angry and frightened.
The correspondent described how a middle-aged man in one of the city's tea shops whispered: "I really want change - but they have guns and we don't, so they'll always win."
Reports from Rangoon said around 25 more monks were arrested by security forces in a raid on a temple overnight.
Meanwhile, Reuters reported about 80 monks and 149 women believed to be nuns had been freed. They had been rounded up as part of the military's violent crackdown on protesters last week.
The authorities said 10 people were killed during the demonstrations - which continued for about two weeks.
Diplomats and activists believe the number of dead is many times higher.
Hundreds of monks - who led the protests - have been detained and sources have told the BBC they will be sent to prisons in the far north of the country.
Other protesters are also said to be missing.
On Tuesday the UN's top human rights official, Louise Arbour, called on the junta to give "precise and verifiable information" on the number of dead and injured as well as "the whereabouts and condition of those who have been arrested".
A Burmese army officer, who fled to Thailand in the first apparent defection since the crackdown, has been giving interviews to media organisations.
The officer, whose unit was ordered to Rangoon to deal with the protests, said he did not want to beat or shoot monks - who are revered in Burmese society.
"I knew the plan to beat and shoot the monks and if I stayed on, I would have to follow these orders. Because I'm a Buddhist, I did not want to kill the monks," he said.
The officer is now seeking asylum abroad.
The BBC's Chris Hogg says that this is a rare split in the ranks which dissident groups will attempt to exploit as evidence that some younger officers are opposed to the brutal crackdown by the country's leaders.
So far, though, there is no sign that others are prepared to follow his lead, our correspondent says.