Violent clashes broke out in the Tunisian capital earlier this week on the anniversary of last year's revolution, writes Lassaad Ben Ahmed in Tunis Violent clashes broke out between the security forces and protesters on Habib Bourguiba Avenue in central Tunis on Monday, injuring several security officers and more protesters, including one reporter and several members of the opposition. The clashes began with a peaceful march to commemorate the 1938 uprising against French colonialism in Tunisia, with the marchers raising banners praising the country's martyrs and their sacrifices and chanting, "Allegiance to the blood of the martyrs!" However, the initially peaceful march soon turned into a pitched battle with the security forces, who tried to clear the protesters from Habib Bourguiba Avenue, which runs through the centre of the city. The security forces used batons and tear gas, with the demonstrators criticising the use of what they said was unnecessary and excessive violence against them. The clashes continued for several hours, with the arrival of security reinforcements and more demonstrators joining the protesters exacerbating the situation. Well-known figures such as leftist activists Hama Al-Hamami and Jawhar Mubarak also joined the demonstration. Eyewitnesses said that groups of bearded men had joined the security forces armed with batons and assaulting protesters and passers-by indiscriminately. The clashes spilled over onto nearby Mohamed V Street and side streets in the centre of the capital, with hit-and-run attacks taking place between unarmed protesters and the security forces. "Black Monday", "fascist behaviour", "savagery" were among the harsh comments after some of the worst violence since last year's revolution that led to the downfall of Tunisian strongman Zein Al-Abidine bin Ali. The Ministry of Interior in Tunisia banned demonstrations on the main streets of the capital after attacks on marchers had taken place by Salafis using the streets for prayer. The ministry issued a statement saying that the earlier demonstrators had not been issued with a permit, though this position was denounced by opposition activists, who said that they had a right to protest peacefully following last year's revolution. Some opposition figures compared the authorities' use of "excessive and brutal force" to the practices used by the police under the rule of former president Bin Ali, who was removed by the revolution in January last year. Al-Hamami, who is the leader of Tunisia's far-left Labour Party, accused the Al-Nahda Movement of having been involved in the clashes, hiring militias to assist the Ministry of the Interior in assaulting protesters. This was immediately denied by the interior minister, who said that the security forces did not need reinforcements. An Al-Nahda Movement spokesman denied that the Movement had been involved in the clashes. Al-Hamami's allegations did not make any sense, he said, since Al-Nahda already controlled the Tunisian government, having won the largest number of seats in last year's parliamentary elections. Tunisian Prime Minister Hamadi Jebali is a leading figure in the Al-Nahda Movement. Al-Nahda Party chief on Tuesday condemned the violence, but dismissed suggestions that the country was tipping back towards authoritarian rule. "Tunisia is not threatened by dictatorship it is threatened by chaos," Rached Ghannouchi said. Al-Nahda would prosecute those making false statements against it, Jebali said, describing the comments as being part of a "conspiracy" against the movement. An official investigation would be held to find out who the perpetrators of the violence were and who was behind them, he said. To highlight their outrage at the police conduct, 15 opposition figures led a group of several hundred in a march on Bourguiba Avenue, after receiving permission from the Interior Ministry. There they managed to meet with the minister of interior for few hours to discuss the violations that happened during the clashes. "We want to defend the Tunisian revolution that is seriously threatened," said Maya Jribi of the opposition Democratic Progressive Party, one of the march leaders. Tensions continued to run high on Tuesday, with the opposition bloc in the Tunisian constituent assembly charged with drafting a new constitution withdrawing from proceedings.