Muslim insurgents in southern Thailand have adopted a new tactic in their fight against the government. They are bombing mobile telephone relay transmission infrastructure and disrupting communications in the turbulent region.
The government says the attacks were probably in retaliation for new restrictions on cell phones aimed at preventing militants from using them to detonate bombs.
On Friday a five-kilogram bomb exploded near a mobile phone antenna in the Thai province of Narathiwat, leaving one man dead.
The bombing followed attacks on Wednesday that targeted dozens of mobile phone transmission stations and antennas in four southern Thai provinces, and partially crippled the network.
The company most affected by the attacks was D.T.A.C. - Thailand's second largest service provider.
Ketchayong Skowratananont, is a department head for D.T.A.C. He says the militants are targeting the mobile phone infrastructure to maximize disruption.
Mr. Ketchayong said, "I think now mobile phones are maybe just like electricity or water or transportation - we now become the public services. So then it's possible - it becomes a possible target for all the militants if they want to create some sort of crisis."
But Ketchayong says the system will be back to normal within weeks and the company is stepping up security along the network.
The Thai government says the attacks are most likely in response to its recent efforts to prevent militants from detonating bombs using the signals from local mobile phones as well as those from neighboring Malaysia.
The government has stipulated that all mobile phone cards must be registered and talks are underway with Malaysia to block mobile phone signals crossing into Thailand's southern border provinces.
Thai police say Friday's explosion was likely to have been triggered by a phone with a Malaysian number.
Zachary Abuza, a political science professor at Simmons College, Boston and a specialist on Islamic militancy in South East Asia, says the government's registration strategy has paid off.
Mr. Abuza said, "Guerillas are inherently conservative. They have limited capabilities. Though there have been improvements in bomb technology, the fact is the cell phone regulations have worked."
But Abuza says the bombings are likely to continue despite the government's efforts. He says the militants' bomb-making capabilities have improved.
Mr. Abuza said, "The technical capacity has gone up. If you look, since 2004 they started with two-kilogram pipe bombs, they graduated, they crossed the five-kilogram threshold, they got beyond the 10-kilogram on a regular basis. They're up to 50 kilograms on occasions. They're using different bombs - they're using TNT, they're using ammonium nitrate…."
Since the current insurgency erupted in southern Thailand in early 2004, more than one thousand people have been killed in bombings, drive by shootings and other violence, with the main targets state officials and the security forces.
The Thai government blames the violence on a mix of factors - Islamic separatists, organized crime and local corruption.