"The world's attention must remain on Myanmar, where I've been appalled by heartbreaking violence against civilians and inspired by the nationwide movement that represents the voice of the people," said Obama, who visited the country to support its nascent embrace of democracy a decade ago.

"The military's illegitimate and brutal effort to impose its will after a decade of greater freedoms will clearly never be accepted by the people and should not be accepted by the wider world," Obama said in a statement.

Obama, who is sparing in his comments on international affairs, backed efforts by the United States under President Joe Biden and other nations to "impose costs on the military" in a bid to restore democracy.

"Myanmar's neighbors should recognize that a murderous regime rejected by the people will only bring greater instability, humanitarian crisis, and the risk of a failed state," he said.

He was speaking on the heels of an ASEAN summit in Jakarta to which junta chief Min Aung Hlaing was invited, with host Indonesia urging an end to violence.

Myanmar's military on February 1 overthrew the elected government and arrested democratic leader Aung San Suu Kyi.

It has harshly cracked down on democratic protests, killing more than 700 people.

Obama in his statement used the name Myanmar, the preferred usage of the Southeast Asian nation's leaders which his administration had gradually adopted.

Since the coup, the Biden administration has gone back to the former name Burma.