BANGKOK - Thailand on Friday destroyed six tons of narcotics worth 276 million dollars to mark the UN's annual day against drugs, as the government vowed to step up its campaign against illegal substances.

The drugs, which were gathered as evidence in nearly 4,500 court cases, were burned in an incinerator in front of public health officials.

"Drugs present a serious threat as they destroy the brain, the family, and social and national security," deputy prime minister Suthep Thaugsuban said at a meeting of state anti-drug officials.

"Therefore the government has put drugs on the national agenda, to stamp them out swiftly to protect younger generations," he said.

The drugs burned on Friday included 2.7 tons of methamphetamine, 2.9 tons of marijuana, 228 kilos (500 pounds) of heroin and 10 kilos of ecstasy tablets.

Nine kilos of cocaine and 3.1 kilos of ketamine were also destroyed.

The total street value of the drugs was estimated at 9.4 billion baht (276 million dollars).

Friday marks the United Nations' International Day against Drug Abuse and Illicit Trafficking.