* Fear of violence prompts call for cancellation of marches
* Feb. 17 is second anniversary of anti-Gaddafi uprising
* Discontent reigns in east over lawlessness, neglect
* Benghazi was cradle of revolt, now hub of autonomy demands
By Ghaith Shennib
BENGHAZI, Libya, Feb 15 (Reuters) - Pro-autonomy leaders in eastern Libya urged followers to cancel planned rallies against central authorities on Friday for fear they could ignite violence as the country marks two years since the start of its revolution.
Various opposition and interest groups in Benghazi, fount of the 2011 uprising that ousted dictator Muammar Gaddafi, have prepared mass demonstrations later in the day to demand better security and investment for Libya's second biggest city.
"Everyone is carrying weapons in Benghazi and there is still general chaos and confusion," activist Zeid el-Ragas said. "As activists it's our responsibility to minimise harm in our city, so we will stay home on Feb. 15."
While Sunday will be the actual two-year anniversary of the start of the anti-Gaddafi revolt, celebrations were to begin later on Friday in remembrance of the arrest of a human rights lawyer in Benghazi that kindled unrest.
Many Libyans, particularly those in the east, have been urging citizens to take to the streets to voice their discontent over the Tripoli government's inability to provide security by disarming militias or moving towards writing a constitution.
Security is a particular headache in Benghazi where violence against foreigners and police assassinations by inchoate Islamist militant groups have become regular occurrences.
On Jan. 25, Britain urged their nationals to leave Benghazi, citing a "specific and imminent" threat to Westerners days after a deadly attack by Islamist militants on a natural gas complex and taking of hostages in neighbouring Algeria.
In Benghazi, the base of the rebel leadership during the 2011 war, daily life has been disrupted by violence and unrest on top of demands for greater autonomy or investment in a region separated from Tripoli 1,000 km (620 miles) away to the west.
This has led to calls in the region - where most of Libya's oil wealth lies - for a return to a federal political structure, that is, more regional autonomy, which Libya had before Gaddafi seized power in a coup in 1969.
Federalist groups say they have come under harsh criticism from the central government and even religious leaders accusing them of calling for a separation of the east from the west of Libya, something they deny they want to do.
"We have been demonised in the state media as traitors and if anything goes wrong on February 15 we will be blamed for it, so it is better if we stay home," Ragas said.
It was not clear how many people would still rally in central Benghazi squares after Friday prayers.
"REVOLUTION NOT OVER"
In September, civilians stormed militia bases in Benghazi after a militant assault on the local U.S. diplomatic mission in which the U.S. ambassador was killed. This happened after an anti-militia "Save Benghazi" rally.
Fearing a repeat, militias have been keeping a low profile in the run-up to the weekend, some of them removing weapons from their bases. More security checkpoints were set up around town.
Long a pro-autonomy hotbed behind earlier attempts to unseat Gaddafi, Benghazi is now the focal point of a widespread sense that the new Tripoli authorities are still ignoring and neglecting the east of the vast North African state.
The over-arching issue is what status Benghazi will have in the new Libya and what stake in national oil supplies of 1.6 million barrels a day - much of it extracted in the east.
"We don't feel like it is a real celebration in Benghazi," said student Samia Ali, 22. "The revolution started here and it is not over yet. We need so many things fixed and Tripoli doesn't listen to our needs - especially our economy."
However, like in Tripoli, hundreds of small tricolour national flags have fluttered in Benghazi throughout the week, and buildings have been decorated with colourful lights.
In Tripoli, drivers in cars adorned with Libyan flags honked horns and blasted patriotic music. Security was tight with a slew of police and pro-government militia checkpoints checking licence plates, registration papers and car boots.
As part of the increased security measures over the weekend, Prime Minister Ali Zeidan said overland borders with Tunisia and Egypt would be closed. (Additional reporting by Hadeel Al-Shalchi in Benghazi, Marie-Louise Gumuchian in Tripoli; Writing by Hadeel Al-Shalchi and Marie-Louise Gumuchian)