The Pheu Thai Party has dismissed suggestions that it was behind the Myanmar protests against the Koh Tao murder case ruling.
The move came after Deputy Prime Minister Prawit Wongsuwon said he believed the protests had been instigated by those who want to cause problems for the government.
While he did not name anyone in particular, Gen Prawit insisted those behind the protests intend to prevent the government from working smoothly.
Police are investigating who, particularly those in Thailand, might have been involved in instigating protests against the ruling, Gen Prawit said.
His comment came amid demonstrations in Myanmar against last Thursday's sentencing to death of Myanmar migrant workers Zaw Lin and Win Zaw Htun, both 22, for the murders of British backpackers Hannah Witheridge, 23, and David Miller, 24, on Koh Tao in Surat Thani province in September 2014.
- EDITORIAL: Police image taints case
- Earlier report: Foreign ministers urge calm
Acting Pheu Thai spokesman Anusorn Iamsa-ard insisted Tues that the party had nothing to do with the protests, and said the military government should not resort to discrediting the party.
"The government should not put all the blame on former prime minister Yingluck Shinawatra. She was an elected prime minister and surely has a sense of social accountability," Mr Anusorn said.
He referred to two photos that went viral on social media, saying the military tried to link the two images.
One photo featured a Myanmar demonstration leader during protests and the other showed the rally leader giving flowers to Ms Yingluck.
"It was wrong to make such claims based on these photos to discredit others," Mr Anusorn said.
Meanwhile, about 100 protesters in Myanmar's Kawthaung province staged a protest against the death sentence near a pier across the border from Thailand's Ranong province.
The protesters, including monks, held up placards with messages written in Myanmar and English expressing disagreement with the ruling, with Myanmar security forces deployed to maintain order in the area.
The protest lasted about an hour before the demonstrators dispersed.
On the Thai-Myanmar border in Chiang Rai's Mae Sai district, the situation was calm and normal Tuesday.
National Security Council secretary-general Thawip Netniyom Tuesday said the NSC is looking into claims that the Myanmar protests were instigated by others to disrupt the government's work.
He said he had instructed intelligence agencies to work with the Thai embassy in Myanmar and foreign intelligence agencies to gather information on the matter.
Gen Thawip added that so far the issue has had no effect on cross-border trade between Thailand and Myanmar.
Myanmar's Tachilek governor Tin Win Shwe earlier insisted the protests against the death sentence were spontaneous, not orchestrated. The governor said Myanmar people only wanted to seek transparency in the case.
Following a discussion with his Myanmar counterpart Tuesday, Foreign Minister Don Pramudwinai said Wunna Maung Lwin understands Thai judicial procedures.
Mr Don said both men agreed that they do not want the protests to get out of hand and affect relations between the two countries.
The Foreign Ministry also reported that about 200 protesters gathered in front of the Thai embassy in Yangon to hand over a letter seeking justice for the two Myanmar workers.
They dispersed after an embassy official received the letter.
The ministry also said that about 30 Myanmar nationals handed a letter to the Thai embassy in Canberra, Australia before dispersing.
In Kuala Lumpur, about 40 Myanmar citizens also gathered at the Thai embassy, though Malaysian police asked them to move their rally to the Myanmar embassy instead. There were no reports of any violence.
Commenting on the Koh Tao case, Prime Minister Prayut Chan-o-cha urged the media to avoid making reports that could lead to conflicts between neighbouring countries.
He said the Myanmar government has not pressured Thai authorities, and that they only want to ensure justice.
Pol Gen Jarumporn Suramanee, a forensic expert who played a key role in gathering and analysing the DNA evidence in the Koh Tao murder case, told the Bangkok Post that the DNA evidence was crucial to linking the two Myanmar migrant workers to the crime.
Pol Gen Jarumporn, who retired as an adviser to the Royal Thai Police in October, said that the bodies of the two victims were sent for autopsies immediately. "I oversaw the autopsy procedure myself."
He said the DNA evidence included semen samples collected from Witheridge's body.
A lock of golden hair was also found in the hand of the victim. Initially, investigators conducted DNA tests on several foreigners on Kao Tao to see if their DNA matched with the DNA found on the victim, but none matched, Pol Gen Jarumporn said.
"Initially, police targeted Westerners, not Myanmar people, given that the hair found in the victim's hand was golden," he said.
However, forensic experts from three universities -- Chiang Mai University, Prince of Songkla University and Chulalongkorn University -- who were asked to help with the DNA checks confirmed that DNA found in the vagina and the rectum of the victim belonged to men of Asian origin, Pol Gen Jarumporn said.