BANGKOK Thai Prime Minister Thaksin Shinawatra vowed Saturday to take decisive action against protesters blamed for causing a dozen injuries after they staged a demonstration opposing a Malaysian pipeline plan.

"My government is ready to take the utmost decisive action against any violent mob," he in his weekly radio address.

Thaksin said 15 police officers were injured in the clash late Friday, while protesters said many villagers opposing the projects were also hurt when some 1,000 police in riot gear baton-charged them.

The group of about 2,000 protesters were gathering near the Dusit JB hotel in the southern city of Hat Yai ahead of a joint cabinet meeting of Thai and Malaysian ministers due to be held there on Sunday.

Protest leader Ananta Boonsopon said the group was assembling peacefully when they were attacked, and denied Thaksin's claims that they were armed with bullets and slingshots.

"Many have suffered minor injuries after being hit on the head and the back but three have been hospitalised and remain in hospital now," he told AFP.

"The authorities tried to paint a negative picture of the protest. The government ordered the demonstration to be dispersed," he said.

But Thaksin said he stood by the actions of the security forces, and threatened to proceed against leaders of the non-governmental organisations (NGOs) who organised the protest.

Blacklisting NGOs

"The government is ready to cooperate with good NGOs but NGOs who rely on violent means will be blacklisted. The government will not tolerate any mob rule," he said.

"I will stand by officials, policemen and security officers to implement decisive action," he added.

Hat Yai, the main city in Songkhla province, was under tight security Saturday, with roadblocks erected and 2,000 police deployed. Television reports said 10 protest leaders had been detained.

Thailand's government has vowed to go ahead with the billion-dollar gas pipeline, which will link southern Thailand with an offshore field being jointly developed with Malaysia, despite objections by residents and environmentalists.

The pipeline was originally due to begin operation this year, with the first stage of the project expected to cost one billion dollars.

But the plan has been stalled by strong opposition from Thai environmental groups who say it will destroy fishing grounds and cause other ecological damage.

Under the scheme, the gas will come ashore at Songkhla province, and then be distributed by pipeline to both countries. AFP