* Protesters say nothing changed since revolution
* Crowd demands caretaker government step down
* Witnesses say thousands more protest in other cities
* Anger that allies of ousted president not jailed
(Updates with more protests)
By Tarek Amara
TUNIS, Aug 15 (Reuters) - Tunisian security forces used teargas and truncheons on Monday to disperse a crowd of protesters in the capital demanding the government step down for failing to prosecute supporters of the ousted president.
Thousands of people also gathered for protests in towns and cities elsewhere, in the biggest show of popular anger in months in Tunisia, a North African country whose revolution at the start of this year inspired the “Arab Spring” uprisings.
Several hundred protesters tried to assemble in front of the Interior Ministry headquarters, on the central Bourguiba Avenue.
“We need a new revolution ... Nothing has changed,” one protester, Mounir Troudi, told Reuters. “This government should leave right now.”
Police, who were gathered in large numbers in front of the interior ministry, fired teargas canisters and hit some of the protesters with truncheons, forcing them to scatter.
Tunisia electrified the Middle East in January when mass protests forced longstanding leader Zine al-Abidine Ben Ali to flee to Saudi Arabia. Tunisia’s revolution became the template for uprisings rippling across the region.
However, the caretaker authorities now running the country have struggled to restore stability. Protests and strikes break out regularly.
Some groups involved in toppling Ben Ali say he and his supporters should have been prosecuted more vigorously and they suspect some in government of sympathising with the ousted administration.
There was an outpouring of anger after the justice minister under Ben Ali was released from jail and a high-profile friend of the ex-president’s wife fled to Paris without facing trial.
Ben Ali himself has been tried and found guilty in asbentia on charges including theft, corruption and illegal possession of drugs and weapons, receiving sentences of up to 35 years.
Many Tunisians contrast that with Egypt, where former president Hosni Mubarak and his sons have been put on televised trial, appearing in the courtroom inside a cage.
Protesters in front of the Interior Ministry chanted: “Ben Ali is in Saudi Arabia and his clan is still here!”
Another protester, Meriam Nafti, said: “Look at Egypt. Mubarak is up before the court together with his sons and the symbols of his regime. Why is it that in Tunisia, the source of the revolution, these things don’t work?”
Witnesses in the city of Sfax, about 250 km (150 miles) south of Tunis, said about 1,000 protesters gathered to demand the resignation of interim prime minister Beji Caid Sebsi and his government.
Residents in Sidi Bouzid, in central Tuinsia, said protesters assembled in front of the town’s courthouse.
It was in that town that street trader Mohamed Bouazizi set fire to himself last December, unleashing the protests that eventually forced out Ben Ali.
“No one can keep quiet about this pantomime of justice,” Mahdi Horchani, who took part in Monday’s demonstration in Sidi Bouzid, told Reuters by telephone. “We need to establish justice in this country.”
Video posted on social networking site Facebook also showed large-scale protests in towns including Bizerte and Beja in the north of Tunisia, Monastir on the east coast and Djerba in the south near the border with Libya. (Reporting by Tarek Amara; Writing by Christian Lowe; Editing by Peter Graff)