Trade unions and students vowed Saturday to press ahead with strikes and demonstrations against a new youth jobs law despite a compromise plan by President Jacques Chirac to defuse the crisis. In a solemn address carried live from the Elysee palace on television and radio, Chirac said he would ratify the controversial measure but promised immediate modifications. “I believe the First Employment Contract (CPE) can be an effective tool for employment,” he said. But he said he had also heard the “anxieties being expressed by many young people and their parents” over the contract, which allows employers to fire under 26-year-olds during a two-year trial period without explanation. Chirac said he would ask Prime Minister Dominique de Villepin - who fathered the CPE - to take steps to ensure that “in practice no contract can be signed that does not fully include these modifications.”Demonstrators rampaged through Paris and other cities until early Saturday to express their rejection of Chirac’s move, made in an address to the nation late Friday. In the capital, protesters smashed store windows, damaged cars, threw bottles at police and attacked the offices of a member of parliament from the ruling UMP party during a march by more than 2,000 people across the city. Police said 107 people were arrested and two police officers were slightly injured.