Biden said it was "unacceptable" to violence directed at Myanmar protesters after security forces were accused of killing more than 100 people on March 27.

"It was horrible. It was unacceptable horror. Based on the report I received, a lot of people were completely meaningless killed," US President Joe Biden told reporters in the state.

The statement comes after Myanmar security forces are accused of killing at least 107 protesters, including seven children, when the country commemorates Armed Forces Day on March 27.

US President Joe Biden at New Castle Airport, Delaware State, on March 26.

The European Union (EU) also called the violence in Myanmar on March 27 "unacceptable".

Defense Minister of 12 countries, including the US, England, Japan and Australia, the same day also called on Myanmar troops to stop using violence, as well as efforts to recover the respects and beliefs of people

"A professional military must adhere to international standards of conduct and have the responsibility to protect, not harm the people they serve," the 12 countries' Defense Minister issued a joint statement.

The Myanmar army is said to have used violence to suppress protesters at more than 40 locations across the country on March 27, mainly in Mandalay and Yangon, according to the Association for Supporting Political Prisoners (AAPP).

Burmese people have been demonstrating almost daily against the military since the February 1 coup, prompting State Counselor Aung San Suu Kyi and senior officials in the civilian government to be arrested.