Paris, Oct 22 (DPA) Violence erupted Friday between police and strikers at an oil refinery near Paris as the French government tried forcibly to restore the flow of fuel to the country.

The clashes came after the French government requisitioned the refinery at Grandpuits and about two dozen of its striking workers in the interest of national defence.

Any worker refusing to comply with such an order can be sent to prison.

All 12 of the country’s oil refineries have been on strike since Oct 12 to protest President Nicolas Sarkozy’s pension reform, which has led to widespread petrol shortages.

Environment Minister Jean-Lois Borloo said on French television Friday that about one-fifth of the country’s 12,300 service stations were out of petrol.

Government officials have vowed to have service stations replenished ahead of next week’s school holidays. Thursday, Sarkozy criticised strikers for ‘taking hostage people who have done nothing’.

The violence at Grandpuits broke out when police charged strikers who had formed a human chain in front the refinery entrance to prevent their requisitioned colleagues to return to work.

A spokesman for the CGT trade union, Charles Foulard, told BFM television that three people were injured in the skirmish.

‘We are outraged, we are scandalised,’ Foulard said, and added that the union would file a legal complaint against the government action.

The violence erupted as the Senate was preparing to vote on the reform, which gradually raises the retirement age from 60 to 62 by the year 2018.

Following certain approval in that body, the measure must still be approved by a parliamentary committee before it becomes law. It is scheduled to go into effect early next year.

However, unions have vowed to continue their strikes and street protests after passage of the measure, and have scheduled two more days of nationwide protest for Oct 26 and Nov 6.