Libya's "day of rage," inspired by the uprisings in Egypt and Tunisia, was due to have take place on Thursday but began prematurely with clashes overnight in the eastern city of Benghazi, where 38 demonstrators were injured in clashes with security forces.
Libyan opposition sources say they believe the trouble was deliberately provoked by the authorities to undermine tomorrow's main event — and intimidate people into keeping off the streets.
Sporadic trouble has been reported from Benghazi, the country's second city, in recent weeks, and the latest outbreak was linked to protests over the infamous massacre of over 1000 prisoners at Abu Salim in 1996 — a bloody landmark in Muammar Gaddafi's 42-year rule. But like previous unrest, it remains local and has not coalesced into opposition at the national level. So far.
"This could snowball into something big," says Ashour Shamis, a veteran Libyan opposition activist. "There are grievances all over the country. But this looks like a spoiler by the government."
Libya's experience of the "Arab spring" may be different from that of its North African neighbours for several reasons. Its enormous oil and gas reserves and small population (6.5m) mean it is relatively wealthy — four times as rich as Egypt — and can afford to buy off dissent.
It is also far less free than either of its neighbours, with a pervasive secret police and little in the way of a free media or independent institutions. Behind the facade of the popular committees the security state still looks unassailably powerful.
Gaddafi's Jamahiriya or "state of the masses" has seen a revolution in its foreign relations over the last decade since it surrendered the Lockerbie bombing suspects, stopped supporting terrorism and gave up its wepaons of mass destruction.
Economic liberalisation has benefited a small middle class but otherwise there has been little domestic change. Libya is extremely corrupt by international standards, though there is less of the flaunting of wealth by the elite than in Tunisia. Its army and security services, based on strong tribal loyalties, would almost certainly step in with force in the event of serious political upheaval and possibly take over the country completely.
Gaddafi — now the longest-serving of all Arab leaders — remains as vigorous and eccentric as ever. Talk of the succession of his reformist-minded son, Saif al-Islam, has faded recently in the face of resistance by the old guard. Another son, Mutasim, is a rising star as his father's national security adviser.
Like other Arab regimes it is capable of easing tensions by concessions such as raising subsidies to keep food prices down. But plans to release the remaining prisoners of the long-banned Libyan Islamic Fighting Group who have renounced violence pre-date the current unrest.