The United Nations human rights chief said on Thursday that the Thai military government had replaced martial law "with something even more draconian" and called for a return to civilian rule.
Thailand's ruling junta said on Wednesday it had lifted martial law imposed just before a coup 10 months ago. But it invoked a security clause in the country's interim constitution that will mean the military will retain broad powers.
UN High Commissioner for Human Rights Zeid Raad al-Hussein said in a statement the decision "leaves the door wide open to serious violations of fundamental human rights" and "annihilates freedom of expression".
"In effect, this means the sweeping away of all checks and balances on the power of the Government, rendering the lifting of martial law meaningless," he said.