About 100 people and 20 police were injured when officers broke up a crowd protesting against a controversial gas pipeline in the southern Thai border town of Hat Yai. Police arrested 12 leaders of the pressure groups which on Friday night massed 2,000 demonstrators outside the venue where the Thai and Malaysian cabinets held yesterday's joint meeting. Student and rights groups lambasted officials for their baton charge of protesters. Suwit Watnoo, of the non-government organisation October Network, said that Prime Minister Thaksin Shinawatra's statements of support for the police action were a 'declaration of war' against the poor. Protesters insist they were acting peacefully and had not stepped outside a cordon set up around the hotel where the Thai and Malaysian ministers met. However, police claim they collected sticks and two catapults from crowd and that it was the protesters who had acted violently first. 'Violence is not the Thai way,' asserted Mr Thaksin. 'Who taught the protesters to act like that? Such actions are unacceptable to me.' 'I will look unfavourably upon any protests organised by these NGOs. These people have no credibility because they resort to violence,' Mr Thaksin said. The prime minister's criticism is the latest of several attacks on NGOs, particularly over their foreign funding, which some commentators say is evidence of an attempt to weaken popular pressure groups. The National Human Rights Commission said it would investigate the incident to see if the violence could have been avoided. The gas pipeline, several dams and other infrastructure projects have been the target of concerted protests across Thailand, which have aligned grassroots movements and environmental groups against a government viewed as interested only in protecting the interests of big business. A series of academic and environmentalists' studies of the proposed gas pipeline say the project is based on dubious forecasts for energy demand, that it is not economically viable and that public consultation has not followed due process, The studies also support public complaints that the pipeline would damage the environment and seriously harm livelihoods. Many months of protests led the government to announce that the route of the pipeline could be moved by five kilometres. However, critics say this will make no difference. The billion-dollar pipeline will link southern Thailand with an offshore gas field being jointly developed with Malaysia. It was due to begin operation this year, but has been stalled by strong opposition. Gas will be piped to Thailand's Songkhla province before being distributed to both countries.