The United Nations' human rights body and European Union delegation have raised concerns over the 14 student activists recently arrested in Bangkok and called on the government to drop the charges against them and release them.
However, Prime Minister Prayut Chan-o-cha shrugged off the calls, saying Thailand follows its own laws.
The UN's Office of the High Commissioner for Human Rights (OHCHR) for South East Asia has urged the government to drop criminal charges against the students who were arrested last Friday for violating the National Council for Peace and Order (NCPO) ban on political gatherings of more than five people.
The government should review its use of laws that limit freedom of expression and freedom of assembly in line with its obligations under international human rights law, the office said.
"The OHCHR is concerned criminal prosecutions for peaceful assembly and expression that carry long prison terms are not necessary or proportional," it said.
Meanwhile, the European Union Delegation also issued a statement backing the EU Heads of Mission in Thailand, saying the arrests of the students were "a disturbing development".
"The EU believes in the right of all to express peacefully their opinions and calls upon Thai authorities to abide by Thailand's obligations under the International Covenant on Civil and Political Rights. Respect for human rights and fundamental freedoms must be upheld, and military courts must not be used to try civilians," the local EU mission said.
Gen Prayut said he didn't owe the EU and the human rights body any explanations regarding the detention of the 14 activists.
"Thailand has its own laws to follow and the government has given those students several chances but they violated the law repeatedly," the prime minister said.
If those activists had been allowed to continue defying the ban over and over without facing any legal action, others would follow suit, he said.
They should know what problems the nation is facing and if they really want to argue with the government they had better wait for the government they elect, but not this one, said Gen Prayut.
"I never wanted it to be like this, nor do I want to be in this position. I've repeated this message many times," he said.
"I've not abused my power, nor have I violated anyone's rights, except for [the rights of] those who refused to play by the rules ... there have been far more decent students out there," he said.
Meanwhile, supporters of the arrested activists, including students and lecturers from various universities, have visited the Bangkok Remand Prison where the male students were detained and the Women's Central Prison where a female student was kept.
Last Friday, police and soldiers arrested 14 students in Bangkok based on a warrant issued by the military court for allegedly inciting unrest under Section 116 of the Criminal Code, which carries a maximum sentence of seven years in prison.
The charges relate to a demonstration held by the students at the Democracy Monument last Thursday evening, a day after the 83th commemorations of the 1932 Siamese Revolution.
Rangsiman Rome, 23, a Thammasat University law student, said from behind bars that the students were united and remained in good spirits. They would not seek bail if there were any conditions.
Payu Boonsopon, 20, an arrested Khon Kaen University law student, said democracy-lovers should reflect on their next move as the 14 students sacrificed their rights and liberties to stage their rally.
"We should not have acted in vain," said Mr Payu.
His parents are working abroad and his grandparents could not come from Chaiyaphum to visit him.
Viboon Boonpattaraksa, 59, father of Jatupat, an arrested core leader of the Dao Din group, said he and his wife did not think their son and the activist students were misguided in striking a social and political stance against undemocratic moves in this country.
"The 1st Army Region commander said he knows who supported the students financially, but he never arrested anyone. Such a statement just damages the students' reputation," said Mr Viboon.
Lamul Jaeng-rew, 44, the mother of Chonticha Chaengrew, who was detained at the women's prison, said her family wouldn't interfere with the legal process for which her daughter and friends and their lawyers were preparing a defence.
"As parents, we are certainly worried about our daughter's well-being but she can decide what's best for herself," said Ms Lamul.
