European law enforcement agencies have vowed to throw the full weight of the law at cost-of-living protesters after demonstrations across the continent spread and turned violent.

The clampdown follows weeks of unrest that began in France as student opposition to education underfunding. The rallies morphed into continentwide mobilizations against cost-of-living increases, a lack of affordable housing, pension privatization, poor public services and several other issues.

After protesters in France allegedly hurled incendiaries at police on Saturday, prosecutors there say they have launched an attempted murder investigation and intend to put those responsible behind bars.

Minister of the Interior Laurent Nunez backed the move, saying anyone who throws an incendiary device at a police officer has carried out "what I call a murder attempt".

A police officer who sustained burns to his ankle in the incident told Le Figaro newspaper that he and other officers "suddenly found ourselves facing several hundred hostile, well-equipped adversaries", who used a "particularly sophisticated" type of incendiary device, with a liquid that "had a far greater burning capacity than a standard Molotov cocktail".

"We faced hostile individuals who are not protesters," he added.

Fourteen other police officers were injured during the weekend protests in France, which were largely peaceful and involved hundreds of thousands of people taking part without resorting to violence or looting. Officers made more than 770 arrests across France over the weekend, which was significantly fewer than has been recorded in recent weeks.

Protests also took place in other countries, including Germany, which had previously been relatively calm.

Ministers there said they are planning a crackdown after looters and rioters damaged stores and injured more than 100 police officers in a major incident in Frankfurt over the weekend.

Roman Poseck, interior minister of Hesse state, said more than 1,300 police officers had struggled to maintain order, arresting 54 people aged between 13 and 29.

"I was shocked by what I have seen, and there is no point in sugarcoating it," he said. "Things cannot go on like this."

earle@mail.chinadailyuk.com