BANGKOK >> The United States said Thursday there was no justification for Thailand’s military coup and it is reviewing its military relationship and other assistance and engagement with its Asian treaty ally.

Secretary of State John Kerry said Thursday’s coup will have “negative implications” for the U.S.-Thai relationship, but did not announce immediate punitive steps. The State Department said it was reviewing millions in aid.

The bloodless military takeover was a response to months of sometimes-violent political protests, but quickly drew international criticism. The European Union said it was following developments in Thailand with “extreme concern” and called for credible and inclusive elections “as soon as feasible.” U.N. Secretary-General Ban Ki-moon appealed for a prompt return to democratic rule.

Thailand is America’s oldest ally in Asia and a close military partner, but after Thailand’s last military coup in 2006, the U.S. froze military assistance for a year-and-a-half until democracy was restored.

“I am disappointed by the decision of the Thai military to suspend the constitution and take control of the government after a long period of political turmoil, and there is no justification for this military coup,” Kerry said in a statement.

He called for the release of detained senior political leaders of Thailand’s major parties, and voiced concern that media outlets have been shut down. He urged the immediate restoration of civilian government and a return to democracy.

Under U.S. law, sanctions kick in if a country receiving American military aid is judged to have undergone a coup. The Obama administration did not make such a determination when a military takeover took place in Egypt, a country of strategic importance to Washington in the Middle East.

State Department spokeswoman Jen Psaki declined to compare the two cases, but said of the situation in Thailand: “We will be implementing it to the full letter of the law.” She said up to $10 million in bilateral assistance from the department and the U.S. Agency for International Development and other forms of aid could be suspended.

Defense Department spokesman Col. Steve Warren said Thursday that the Pentagon was reviewing its military relationship with Thailand, including a military exercise that began Monday with about 700 Marines and sailors participating. He said officials are looking at various options, but no decisions have been made.

After the 2006 coup that toppled then-Prime Minister Thaksin Shinawatra, the U.S. took nine days before it announced its suspension of military aid, including funds for military sales, training of officers under the International Military Education and Training program, and funding for peacekeeping and counter-terrorism training.

According to a Congressional Research Service report, that response was seen as relatively mild. The suspended programs totaled more than $29 million.