TRIPOLI (Reuters) - Muammar Gaddafi's fearsome security apparatus appears to be weakening in Tripoli, but it is still too powerful to risk an uprising -- that is the view of Libyans who say they are part of a burgeoning underground opposition network in the capital.
The handful of activists, who spoke to Reuters journalists on condition that neither their identities nor the location of the meeting be revealed, said Gaddafi was keeping control of the city through informants, mass arrests and killings.
"No single event will bring down the regime here in Tripoli," said one activist who goes by the name of Niz.
"And it will take time," he added, saying more NATO bombing, a push by Libyan rebels outside the city and better coordination of the opposition inside the capital would probably be needed.
Yet Niz and others also spoke of a system of repression that was showing signs of strain, with a shortage of places to hold detainees, interrogators who do not know what questions to ask and people arrested and then released apparently at random.
That Reuters foreign journalists staying at a tightly monitored hotel were able to slip away from government minders to meet people who said they represented active opposition cells was itself a sign of disarray in the decades-old security system -- a disarray NATO is counting to bring Gaddafi down eventually.
Four activists from two different opposition movements -- groups which have maintained contact with foreign media for the past few months -- gave an account of what they thought it would take for Gaddafi's grip on his Tripoli stronghold to be broken.
It was an assessment that will be sobering for those in Western capitals, and in the rebel-held Libyan cities of Benghazi and Misrata, who have been hoping for a swift end to the four-month old conflict.
An uprising in Tripoli is seen by some NATO member states as the best bet for toppling the Libyan ruler after months of coalition air strikes, and rebel attacks outside the capital, failed to produce a decisive outcome.
"The rebels don't really have a chance of breaking out from the east, making their way to Tripoli," said Shashank Joshi of the Royal United Services Institute in London. "It will rely on some sort of urban uprising within the city itself."
Niz said outsiders, and the eastern rebels, should be patient if they were waiting for Tripolitanians to rise up:
"Four months is a long time for those being shelled," he said of those under siege in Misrata and elsewhere. "It's a long time for those being raped or tortured," he added.
"But, objectively, it's not a long time when you consider the regime has been in power for 42 years."
Niz has been in regular contact with foreign media, speaking for what he calls the Free Generation Movement -- predominantly secular, young and liberal in outlook, inspired by the uprisings that overthrew autocrats in neighboring Tunisia and Egypt.
Quite how many people Niz speaks for is unclear. It may be as few as a dozen people in regular contact with each other in a city deprived of most modern communications beyond basic phone services. But each such group appears to have contacts with many others, suggesting loose, cellular pattern of opposition action.
Those activists Reuters met said an uprising in the capital would require further weakening of Gaddafi's rule by the NATO bombing campaign, significant progress toward the capital by rebels -- and a stronger opposition network within the city.
Building up that network has been made vastly more difficult by the government's decision to shut down Internet and mobile phone text messages. That has deprived Gaddafi's opponents of access to tools that played a big role in Egypt and Tunisia.
"We're having to do things the old-fashioned way," said one of the activists, who used the name Fatima. "That takes time."
Her group, going by the name of the February 17 Young Women's Coalition of Tripoli -- a reference to the date of the first big street protests -- also appears tiny, but also representative of widespread anti-Gaddafi sentiment.
Many dozens of people in Tripoli who have spoken to Reuters discreetly in the past four months echo such views, especially their ultimate goal of ending Gaddafi's 42-year rule.
As a group, the activists Reuters met at a secret location in the city were all well educated. All four had university degrees and spoke English. Ranging in age from their 20s to middle-age, the women wore Islamic headscarves, the men casual Western-style dress of jeans and T-shirts.
Gaddafi's opponents in Tripoli live in fear of arrest. Setting up a meeting between them and Reuters reporters involved elaborate preliminary arrangements by the activists to make sure Gaddafi's intelligence services did not find out about it.
At the meeting, the youngsters who presented themselves as active in an underground opposition network described heavy security across the city, especially at night with numerous checkpoints that shift locations from day to day.
People can be held for anything from hours to days, or even weeks; some have been killed, the activists said. "There are mass arrests every day. There are killings every day," said Niz.
They said some people appeared to have been arrested solely on the grounds of being originally from rebel towns, such as Misrata or Zlitan. At other times, arrests seemed to be based on people's family names. In Libya, these often carry clues about local origins or tribal connections.
Often though, the detentions seem to be pretty much random. "There are no rules," said an activist from the women's coalition who used the name Amal. "Just what they decide."
Libyan officials deny repressing dissidents, and say the overwhelming majority of the population supports Gaddafi. They describe those who do not as criminals and al Qaeda militants.
Rival accounts cannot be independently verified as the government keeps the small international media corps largely confined to a hotel and rarely lets reporters out without an official escort . Groups like Human Rights Watch have reported accounts of mass arrests and torture of dissidents in Tripoli.
Though still powerful, the security apparatus is showing signs of strain, the activists said. Levels of crime seem to have risen on the streets of Tripoli, especially at night, apparently since security men are so focused on preserving Gaddafi's rule they have limited capacity for routine policing.
Civilian loyalists of Gaddafi have been armed by the government and sent out to help in the crackdown on dissent are themselves robbing residents, one of the activists alleged.
"The volunteers took the guns not because they believe in Gaddafi but because they wanted the power," Amal said. "They have taken their chance to make as much money as possible.
"And they are enjoying their power."
Everything from minor infractions such as running a red light or talking on a mobile phone while driving -- officially subject to a 500-dinar ($400) fine -- to public drunkenness in a country where alcohol is banned, is now possible without real fear of falling foul of the police, the activists said.
"It's jungle law out there," said Niz. "There is no law now. There is just the protection of the regime."
The activists said Gaddafi's security services appeared to have become fragmented, to have lost numbers to defections and some interrogation facilities to the NATO bombing campaign.
"Some people are sent to interrogators who have no idea what to ask them," said Salim, a Free Generation Movement activist.
"Some people are arrested who have done many things to get in trouble but are released without interrogation, while others who have done nothing are kept for weeks."
"There is no pattern," he said.
"Some people are released within hours, others are held for days and tortured. Others do not show up again."
Salim described what he called signs of paranoia on the part of some security men -- for example, sending "six cars to arrest someone when before they would send only two".
But activists said a heavy-handed response to calls for reform, the widespread use of informants and shutdown of social media websites, were proving effective in combating opposition -- many people were still too afraid to speak out.
"There are plenty of people, including soldiers, who are anti-Gaddafi," said Amal. "But they can't show it yet because they are afraid.
"They are waiting for the rebels to get closer so that the fighting can be over quickly instead of lasting months."
As an example of why it is too early to expect an uprising in the Libyan capital, the activists cited rumors ahead of June 17, the four-month anniversary of the uprising, that the rebels had some sort of action planned in Tripoli. But when June 17 arrived, last Friday, security was so heavy that there were armed men waiting outside mosques after weekly prayers.
"When the uprising comes it will be spontaneous," said Niz.
"A pre-planned event will be impossible because the regime will be prepared for it. It would be suicide."