Myanmar riot police opened fire on anti-coup protesters in the country's second-largest city Mandalay on Saturday, killing two of them, local media outlets reported.

The incident occurred as a demonstration was being held near the shipyard. After participants surrounded security forces that arrived at the scene, the latter fired, possibly using live ammunition.

People take to the streets in Yangon, Myanmar, on Feb. 19, 2021, to protest against the Feb. 1 military coup. (Kyodo) ==Kyodo

One of those who died was shot in the head, the other one in the chest. About 20 others were injured.

Footage and photos posted on social media showed citizens fleeing from water discharge and some with injured heads and backs.

The two deaths came a day after the first protester to be killed since the protests began following the Feb. 1 military coup died in hospital in the capital Naypyitaw after 10 days on life support.

Earlier Saturday, in the largest city Yangon, a rally was held in memory of the female student, 20-year-old Mya Thwet Thwet Khine, who was shot in the head while participating in a Feb. 9 demonstration.

Authorities say a policeman also died from injuries sustained in a protest, which would bring the total number of deaths since the coup to four.

On Saturday evening, the Foreign Ministry of Singapore, a fellow member of the Association of Southeast Asian Nations, chastised the Myanmar security forces and called for restraint.

"We are dismayed by the reports of civilian casualties following the use of lethal force by security forces against demonstrators in Myanmar. The use of lethal weapons against unarmed civilians is inexcusable," the ministry said in a statement.

"We strongly urge the security forces to exercise utmost restraint to avoid further injuries and loss of lives, and take immediate steps to de-escalate the situation and restore calm."

"If the situation continues to escalate, there will be serious adverse consequences for Myanmar and the region," it warned.

ASEAN, which also includes Brunei, Cambodia, Laos, Malaysia, the Philippines, Thailand and Vietnam, is considering to hold an urgent special meeting of foreign ministers on the Myanmar situation, as proposed by Indonesian President Joko Widodo.

Also Saturday, ethnic minority groups sought the Japanese government's help in securing the freedom of ousted leader Aung San Suu Kyi and other detainees.

Hundreds of anti-coup protesters with the flags of each ethnic group gathered in front of the Japanese Embassy where an ethnic Chin female representative of the protesters read aloud an open letter in Japanese and English requesting support for the liberation of all detained people and the realization of democracy.

Japanese Ambassador Ichiro Maruyama himself received it personally and responded, "We do not ignore the voices of the people of Myanmar. We are calling on the armed forces to release detainees and solve democratic problems."

His remarks prompted applause.

In a related matter, the peace negotiation team of the 10 ethnic minority armed groups that are signatory to Nationwide Ceasefire Agreement issued a statement Saturday saying they have decided to suspend peace talks with "the military junta" and to support the civil disobedience movement.