Security authorities quickly dismissed a claim by Thursday former prime minister Chavalit Yongchaiyudh that an Islamic State (IS) cell was active in the far South of Thailand.
Gen Chavalit said he was wondering if the government was aware that a group calling itself "Black Swan" which, according to him, is an IS affiliate, was establishing a presence in the deep South.
He was responding to a request to comment on security matters during a meeting Thursday with reporters.
Gen Chavalit also urged the government to launch a probe into the Black Swan group and improve the efficiency of its intelligence agency, saying conflicts in the deep South have changed.
The Fourth Army commander, Wiwat Pathomphak, said he has not heard of the Black Swan group and there have been no recent intelligence reports about it.
Security officials were monitoring reports about IS although there have been no signs of IS activity in Thailand so far, said Lt Gen Wiwat.
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Maj Gen Banpot Poonpian, Internal Security Operation Command (Isoc) spokesman, also said he has not received any reports about the Black Swan group.
Several countries in the region have detained suspects linked to IS, making it crucial for Thailand to maintain an effective surveillance programme on any possible signs of IS activity in the country.
A security source, meanwhile, said both the National Intelligence Agency and the Immigration Bureau told a previous meeting of security agencies they had been alerted by their counterparts in different countries that one or two Syrian nationals, who are members of IS, had travelled to Thailand on tourist visas.
According to the source, the two Syrian nationals had travelled to the deep South of Thailand.
This prompted a search for the pair and a security alert both in the deep South and Bangkok, said the source.
Central Investigation Bureau chief Pol Lt Gen Thitirat Nongharnphithak said he has received no reports about IS in Thailand.
Pol Maj Gen Itthipol Atchariyapradit, chief of Yala provincial police, also said he has not received any report about Syrian nationals in the deep South.
Jeh-aming Totayong, a former Democrat Party MP for Narathiwat, challenged Gen Chavalit to prove his claim about IS-linked activities in the restive South.
Mr Jeh-aming said the former prime minister should not resort to spreading rumours to frighten the public without providing proof, or would be no different to other public figures in the Thaksin Shinawatra camp who were lining up to discredit Thailand.
He accused Gen Chavalit of attempting to link the southern unrest with the foreign security issue as part of a political agenda, similar to the way Thaksin was now renewing his push to discredit Thailand from overseas where he is in exile.
Mr Jeh-aming said Gen Chavalit's remarks appear to be an attempt to convey the idea that Thailand's security is lax.
He added he has been working in the deep South for a long time and he has never heard of any IS presence there before.
There was no evidence proving a connection between the southern unrest and IS, he said.