French protestors have blocked key sites and clashed with police as unions called for further 'massive' nationwide protests against President Nicolas Sarkozy's plan to raise the retirement age.

A female student was hospitalised during the latest scuffles that Mr Sarkozy has criticised as 'scandalous'.

With no fuel left in more than a quarter of French petrol pumps, police are playing what unions have described as a game of cat and mouse with protestors at depots and refineries in a bid to prevent the country grinding to a halt.

The head of the powerful CGT union Bernard Thibault said that faced with government intransigence there was 'no reason to stop these protests and we recommend further action from next week'.

'We have to continue with the most massive actions possible,' he told RMC radio.

Unions are to meet this afternoon to decide on holding further mass rallies, possibly on Tuesday, a week after the last protest.

More than 1m people took to the streets then, the sixth day of action since September, to protest against the unpopular plan to raise minimum retirement from 60 to 62 and full pension payments from 65 to 67.

Workers in key sectors have been on strike for more than a week to protest at the reform, which the government says is essential to reduce France's public deficit. Unions and political opponents say it penalises workers.

Mr Sarkozy called days of unrest in the eastern city of Lyon, including looting, 'scandalous' and vowed that 'the troublemakers will not have the last word'.

'This is not acceptable, they will be arrested, found and punished, in Lyon as elsewhere, without any weakness,' Mr Sarkozy said.

Youths have been fighting running battles with riot police in several cities, and a schoolgirl was hospitalised this morning during clashes with police outside a school in the city of Poitiers.

A student representative said the injured girl had three ribs broken after being beaten by a police officer with a truncheon.

Interior Minister Brice Hortefeux said that more than 1,900 people had been arrested so far - 245 people yesterday alone.

Activists blocked access to Marseille airport for several hours before being cleared by police, causing tailbacks of several kilometres.

Troops have also been sent in to clear rubbish from the streets of the Mediterranean port where collectors are on strike, while a similar strike in Toulouse intensified today, with workers blocking access to dumps.

The country's 12 oil refineries have been closed down, and Mr Hortefeux said that 14 of 219 fuel depots were currently blocked by protestors, despite Sarkozy ordering police to keep fuel flowing.

Petrol pump operators appealed to the government to send in riot police, or even the military, to free up depots.

Three-quarters of express TGV trains were running in and out of Paris, although only half of provincial trains were operating.

The pension law has been passed by the National Assembly and is slowly working its way through the Senate, which could pass it tomorrow.