Mayors call for calm while security is enhanced in the suburbs after two nights of riots in the northern suburbs of Paris. Police stepped up security in northern Paris suburbs on Tuesday (November 27) to prevent a third night of unrest, after French Prime Minister Francois Fillon vowed a firm line against rioters who attacked police. Police vans, their sirens blaring and lights flashing, headed towards the northern Paris suburb of Villiers-le-Bel on Tuesday evening as the security build up got underway, a Reuters witness said. Six Socialist mayors in northern Paris suburbs affected by the troubles renewed appeals for calm and urged parents to help them avoid more unrest. They called for calm to avoid exacerbating tensions in France's deprived, ethnically diverse suburbs. "First of all, I appeal for calm so that things calm down in Villiers le Bel," said Didier Vaillant, mayor of Villiers le Bel. He then added : "I ask the families, parents, to keep their children and teenagers at home tonight." Around 80 police were injured overnight as rioters hurled stones, petrol bombs and firecrackers at police during several hours of skirmishes that left dozens of shops, businesses and public buildings damaged. Police replied with tear gas and rubber bullets and made five arrests. Five police officers were seriously hurt overnight, including one hit by a projectile apparently fired from a hunting rifle. President Nicolas Sarkozy will meet Fillon and his interior and justice ministers to discuss the crisis on his return from China on Wednesday (November 28), his spokesman said in a statement. He will first visit injured police officers in hospital. The violence started on Sunday (November 25) after two youths died in a collision with police, and images of burnt out cars, a school and a library revived images of suburban riots two years ago. Those disturbances were the worst civil unrest in France for 40 years and many blamed the harsh rhetoric of Sarkozy, who was interior minister at the time, for stoking the violence.