The United States has canceled an ongoing military exercise with Thailand and planned visits by officials after the Thai army seized power in a widely condemned coup.

Thailand's army said Thursday it had taken power in a coup after months of unrest and deadly political violence, provoking an international outcry and heightening fears for the future of the Asian country and its fragile democracy.

"While we have enjoyed a long and productive military-to-military relationship with Thailand, our own democratic principles and US law require us to reconsider US military assistance and engagements," Pentagon spokesman Rear Admiral John Kirby said in a statement Saturday.

The Cooperation of Afloat Readiness and Training exercise (CARAT), which involves several hundred US Marines and sailors, began Monday and was supposed to run for a week.

The scrapped visits had been planned for June -- one to Thailand by US Pacific Fleet Commander Admiral Harry Harris and another to the US Pacific Command in Hawaii by a high-ranking Thai military official.

"It is important that the Royal Thai Armed Forces end this coup and restore to the people of Thailand both the principles and the process of democratic rule, including a clear path forward to elections," Kirby said.

"We urge the Royal Thai Armed Forces to act in the best interests of their fellow citizens by ending this coup and restoring the rule of law and the freedoms assured those citizens through democratic principles."

The US military has long-standing ties to Thailand's armed forces, dating back to the Korean and Vietnam wars.

Still, the Pentagon also warned of potentially more cuts.

"We will continue to review additional engagements as necessary until such time that events in Thailand no longer demand it," Kirby said.

Word of the cancellations comes on the heels of an announcement by Washington on Friday that it had suspended $3.5 million in military assistance to its oldest treaty-bound ally in Asia.

The US State Department meanwhile said that the United States was reviewing the rest of its aid to Thailand -- which totaled $10.5 million in 2013.

In a statement, State Department spokeswoman Marie Harf said Washington had now also called off a US government-sponsored firearms training program for the Royal Thai Police that had been scheduled to start Monday.

"We are increasingly concerned about actions the military has taken, just a few days after it staged a coup," Harf said, pointing to the dissolution of the Senate, arrests and media restrictions.

"We again call on the military to release those detained for political reasons, end restrictions on the media and move to restore civilian rule and democracy through elections."