Mahn Win Khaing Than, who was named the acting vice president by Myanmar's ousted lawmakers and is a member of deposed leader Aung San Suu Kyi’s party, addressed the public on Saturday for the first time since the Feb. 1 military takeover.

“This is the darkest moment of the nation and the moment that the dawn is close,” he said in a video posted on the shadow government’s website and social media.

“In order to form a federal democracy, which all ethnic brothers who have been suffering various kinds of oppressions from the dictatorship for decades really desired, this revolution is the chance for us to put our efforts together," he said.

He added: “We will never give up to an unjust military but we will carve our future together with our united power. Our mission must be accomplished.”

At the end of the message he flashed a three-finger salute that has become a symbol of resistance to the military rule.

Earlier Saturday, security forces opened fire at demonstrators, killing four in Mandalay, the second biggest city, two in Pyay in south-central Myanmar, and one in Twante, a suburb of Yangon, Myanmar's largest city. Details of all seven deaths were posted on multiple social media accounts, some accompanied by photos of the victims.

The actual death toll is likely to be higher, as police apparently seized some bodies, and some of the victims suffered serious gunshot wounds that doctors and nurses working at makeshift clinics will be hard-pressed to treat. Many hospitals are occupied by security forces, and as a result are boycotted by medical personnel and shunned by protesters.

The independent U.N. human rights expert for Myanmar, Tom Andrews, said last week that credible reports indicated at least 70 people had died so far, and cited growing evidence of crimes against humanity by the military.

Other unofficial but carefully compiled tallies put the number of deaths since the coup at around 90.

Saturday’s killings did not faze demonstrators in Yangon who crowded a downtown commercial area past the official 8 p.m. curfew to hold a mass candlelight vigil and sing about their cause. The mostly young protesters rallied at an intersection where they usually gather for daytime protests.

After-dark rallies was also held in Mandalay and elsewhere.

Reports on social media also said three people were shot dead Friday night in Yangon, where residents for the past week have been defying the curfew to come out onto the streets.

The nighttime protests may reflect a more aggressive approach to self-defense that has been advocated by some protesters. Police had been aggressively patrolling residential neighborhoods at night, firing into the air and setting off stun grenades as part of intimidation. They have also been carrying out targeted raids, taking people from their homes with minimal resistance. In at least two known cases, the detainees died in custody within hours of being hauled away.

Another possible indication of heightened resistance emerged Saturday with photos posted online of a railway bridge said to have been damaged by an explosive charge.

The bridge was described as connecting the rail line from Mandalay to Myitkyina, the capital of the northern state of Kachin. The photos show damage to part of a concrete support.

No one took responsibility for the action, which could be seen as support for the nationwide strike of state railway workers, part of the civil disobedience movement against the coup.

At the same time, it could also disrupt military reinforcements in Kachin, where ethnic guerrillas have been fighting the central government.

The prospect of sabotage has been openly discussed by some protesters, who warn they could blow up a pipeline supplying natural gas to China, seen as the junta’s main supporter.

In Washington on Friday, the Biden administration announced it is offering temporary legal residency to people from Myanmar, citing the coup and deadly force against civilians.