Dozens of people were killed by security forces during protests on the deadliest day since last month's military takeover of the country.

The killings, reportedly of more than 100 people, show "that the junta will sacrifice the lives of the people to serve the few," Mr Blinken said.

"The courageous people of Burma reject the military's reign of terror."

The US embassy previously said security forces were "murdering unarmed civilians", while the EU delegation to Myanmar said Saturday - officially Armed Forces Day - would "stay engraved as a day of terror and dishonour".

UN Secretary-General Antonio Guterres said he was "deeply shocked", and British Foreign Secretary Dominic Raab called it a "new low".