Human rights groups in Thailand have condemned the high death rate in recent anti-drugs operations.

The police crackdown began on 1 February, and so far more than 350 people are reported to have been killed and 9,000 arrested.

The human rights group Amnesty International told the BBC Thai service it had grave concerns about any extra-judicial killings, saying they were only justified in cases of self-defence.

The government is firm in this policy. Don't worry, whoever wants to criticise, let them criticise Thaksin Shinawatra, Thai Prime Minister

Thai Prime Minister Thaksin Shinawatra told reporters that only 13 suspects had been shot by police, and that violence within drug gangs was responsible for the rest.

But Amnesty's Srivak Philat said the police had committed human rights violations.

They should "adhere to the rules that people are innocent until proven guilty", he said, adding that "only the courts can pass judgement."

Mr Thaksin brushed off the criticism, saying: "The government is firm in its policy. Whoever wants to criticise, let them criticise."

Thaksin Shinawatra has defended his hardline approach

The campaign was part of an initiative led by the prime minister, who came to office two years ago promising to rid Thailand from the scourge of drugs.

But he has largely been unable to stop the flow of millions of highly addictive methamphetamine pills from Burma, which are widely used in Thailand by people of all ages.

Thai police say they are bracing themselves for a billion pills from Burma alone this year.

There are thought to be at least a million methamphetamine addicts in Thailand, which is known locally as "ya-ba".