Students from Ramkhamhaeng University gather in front of the Singaporean Embassy in Bangkok yesterday to protest against the meeting earlier this week between Singapore’s deputy prime minister and ousted premier Thaksin Shinawatra.

The military junta yesterday threatened to exercise its power to revoke the licences of Singaporean-owned telecom and satellite operators if they were found to be wiretapping communications channels and sending sensitive information back to the city-state.

For security reasons, the eight members of the Council for National Security changed their cellular provider from Singaporean-controlled Advanced Info Service to other firms, said junta spokesman Colonel Sansern Kaewkamnerd.

Information and Communica-tions Technology (ICT) Minister Sitthichai Pookaiyaudom said Singaporean-owned mobile-phone and satellite operators would lose their licences if they were caught eavesdropping on customers.

Junta chief Sonthi Boonyaratglin on Wednesday said all mobile-phone conversations were being picked up and relayed to Singapore, so that the country could spy on Thai security.

Yesterday, he said the junta was "concerned about the operation of mobile phones and satellites whose concessions were transferred to a foreign country".

Singapore's investment arm, Temasek Holdings, bought Shin Corp - which owns the biggest players in the local mobile-phone and satellite businesses - from the family of deposed Premier Thaksin Shinawatra.

Sonthi raised his concerns amid a diplomatic stand-off with Singapore for allowing Thaksin to meet its deputy prime minister, S Jayakumar, and use the city-state as a launching pad for interviews with international media to cast aspersions against the junta and military-installed government.

The ICT Ministry called all telecom and satellite operators, including Shin Satellite, to a meeting and reiterated to them that the junta would cite its 21st Announcement in putting them out of business if they conducted electronic surveillance of signal transmissions, said ministry spokesman Wissanu Meeyu.

All the operators insisted to the ministry that they had never condoned such practices, he said.

As a group of students staged a protest in front of the Singaporean Embassy, and residents in the northeastern province of Udon Thani urged the Thai military to return second-hand jet fighters, a key junta member rushed to soothe passions before the anti-Singapore sentiment spiralled out of control.

General Saprang Kalayanamitr, assistant to the Army chief, refuted a local media report that the military might review an agreement for Singapore's military to use a Thai airbase as its exercise ground.

He told reporters the ongoing diplomatic spat would not set back military cooperation between the two countries.

Chareon Mookachornphan, a coordinator of the Udon Thani-based People's Assembly, said the retaliation taken by the government against Singapore - suspending a few bilateral meetings - was not enough for the mistake the city-state made in letting its deputy premier speak with Thaksin.

In 2005, Singapore donated seven F-19A/B jet fighters - three Alphas and four Bravos - to Thailand during the Thaksin administration in exchange for the right to use the Wing 23 airbase in Udon Thani for 15 years to train its military.

More than 100 police were stationed at the Singaporean Embassy for fear the students staging a noisy protest there planned to burn the mission down.

One student dismissed the rumour, saying they just wanted to air their anger at Singapore.

A group of six Ramkhamhaeng University students gathered in front of the embassy to demand an explanation within three days of why the republic allowed Thaksin to do what he did.

They waved signs reading, "This is Thailand. Don't look down on your neighbour," and, "Singapore, get out." Another said, "We know what you think."

They said they represented the Thai Students' Network for Democracy and were not being paid to demonstrate.

Former Foreign Minister Surin Pitsuwan called on the government to control nationalistic reactions in dealing with the matter. Otherwise, the situation could turn ugly, like what happened between Singapore and the Philippines when the city-state hanged a Filipina maid.