By Dan Collyns BBC News, Lima

Peru is the biggest producer of cocaine after Colombia

A team of almost 200 workers were fired upon from the jungle as they destroyed an illegal plantation of coca - the raw ingredient used to make cocaine.

The latest attack comes as the Peruvian government has declared open war on cocaine production.

It is thought to be the first time snipers have fired on such a large group of civilian workers.

Tough stance

While the identity of the attackers is still unclear, police say the area of Yanajanca where the attack took place is controlled by remnants of the Shining Path rebel group led by "Artemio" - the only guerrilla leader still at large.

Critics say President Alan Garcia is talking tough to impress the US

The attack comes as the Peruvian authorities re-started coca eradication after it was suspended for two weeks to pacify coca farmers who blocked a main road.

At the beginning of the month, the Peruvian president, Alan Garcia, appeared to toughen his stance ordering the use of warplanes to destroy clandestine airstrips and drug laboratories in the Amazon jungle.

Although these methods are unlikely to be put into practice, the announcement of a new zero-tolerance approach will mean more soldiers deployed in coca-growing regions and a new wave of eradications.

This is likely to provoke more confrontations and critics accuse Mr Garcia of talking tough in an attempt to impress the US.

Later this month, President Garcia will visit Washington to try to ratify a free trade agreement which had been thrown into doubt by the Democrat-led congress.

Peru allows a certain amount of coca leaf to be legally cultivated for traditional and medicinal use, but this makes up less than 10% of the 100,000 tonnes of the leaf produced in the country.

Peru is the second biggest producer of cocaine after Colombia and recent years have seen a rise in production and the greater presence of drug-trafficking cartels.