Myanmar's military leaders came under renewed pressure at home and abroad on Tuesday with joint condemnation from the G7 countries, tightened sanctions from Washington and Brussels and some of the biggest demonstrations against their rule since they seized complete power three weeks ago.

The foreign ministers of the G7 countries said on Tuesday they "firmly condemn" violence committed by Myanmar's security forces against protesters and urged them to "exercise utmost restraint and respect human rights and international law".

Three anti-coup protesters have been killed in demonstrations so far, while a man patrolling his Yangon neighbourhood against night arrests was also shot dead on the weekend.

"Use of live ammunition against unarmed people is unacceptable," the foreign ministers of the G7 group of rich democracies -- comprising Canada, France, Germany, Italy, Japan, Britain, the United States together with the EU said in a statement Tuesday.

Three anti-coup protesters have been killed in demonstrations so far, while a man patrolling his Yangon neighbourhood against night arrests was also shot dead on the weekend.

Overnight the US blacklisted another two members of the regime -- air force chief Maung Maung Kyaw and fellow junta member Moe Myint Tun -- after announcing targeted sanctions against other top generals earlier this month.

"We will not hesitate to take further action against those who perpetrate violence and suppress the will of the people," Secretary of State Antony Blinken said.