Myanmar security forces opened fire on some of the biggest protests against military rule in days, killing at least five people on Sunday, media reported, three months after a coup plunged the country into crisis.

Explosions blasted off throughout Myanmar's largest city Yangon on Saturday as protesters held flash marches for democracy, defying a brutal junta that has held onto power for three blood-drenched months.

Myanmar anti-coup activists launched protests on Wednesday calling for the release of detained prisoners, as junta chief General Min Aung Hlaing was reported to be planning to attend a regional summit to discuss the crisis in the country.

Myanmar authorities detained a Japanese journalist in Yangon on Sunday evening, Japan's government said on Monday, adding that it was trying to seek his release.

Myanmar security forces opened fire on pro-democracy protests on Saturday killing five people, a protester and media said, as the military reinforced its bid to end dissent with arrest warrants for online critics and internet blocks.

Opponents of military rule in Myanmar marched and laid bouquets of flowers on Friday while trying to find alternative ways to organise their campaign of dissent after the authorities cut off most users from the internet.

The United States on Wednesday ordered the departure of non-essential diplomats from Myanmar, amid growing violence following the military coup to oust civilian leader Aung San Suu Kyi.

Rubbish piled up on the streets of Myanmar's main city on Tuesday after activists launched a "garbage strike" to oppose military rule as the toll of pro-democracy protesters killed by the security forces since a Feb. 1 coup rose to more than 500.

Myanmar security forces shot and killed three anti-junta protesters on Friday, witnesses said, as the World Bank warned the country's economy could slump 10% this year due to the turmoil since last month's coup.

Demonstrators in Myanmar maintained their dogged opposition to military rule on Sunday despite a rising death toll, with two more people killed as the junta appeared equally determined to resist growing pressure to compromise.

Opponents of Myanmar's coup protested again on Saturday and international pressure on the military junta to halt its repression of democracy supporters increased, with Asian neighbours joining Western countries in condemning lethal force.

Myanmar security forces shot dead nine opponents of a Feb. 1 coup on Friday, a funeral services provider and media said, as Indonesia urged an end to the violence and the restoration of democracy, in an unusually blunt call from a neighbour.