YANGON, Myanmar (AP) — Security forces in Myanmar made mass arrests and appeared to use lethal force on Sunday as they intensified their efforts to break up protests a month after the military staged a coup.

There were reports of gunfire as police in Yangon, the biggest city, fired tear gas and water cannons while trying to clear the streets of demonstrators demanding that the elected government of Aung San Suu Kyi be restored to power. Photos of shell casings from live ammunition used in assault rifles were posted on social media, adding to evidence that live rounds were fired.

A violent crackdown also occurred in Dawei, a much smaller city in southeastern Myanmar, where local media reported at least three people were killed during a protest march. The fatalities could not immediately be independently confirmed. Confirming reports of protesters’ deaths has been difficult amid the chaos and general lack of official news.

The Feb. 1 army takeover reversed years of slow progress toward democracy after five decades of military rule. Suu Kyi’s National League for Democracy party would have been installed for a second five-year term in office, but the army blocked Parliament from convening and detained her and President Win Myint, as well as other top members of her government.

Sunday’s violence erupted in early morning when medical students were marching in Yangon’s streets near the Hledan Center intersection, which has become the gathering point for protesters who then fan out to other parts of the city.

Videos and photos showed protesters running away as police charged at them, and residents setting up makeshift roadblocks to slow their advance. Nearby, residents were pleading with police to release those they picked up from the street and shoved into police trucks to be taken away. Dozens or more were believed to have been detained.

There was no immediate word on Yangon casualties. Sounds of gunfire could be heard in the streets and there were what appeared to be smoke grenades thrown into the crowds.

Demonstrators later Sunday regrouped and were said to be planning to march to the local police station to demand the release of the medical students.

In Dawei, video from the online media company Dakkhina Insight showed a young man receiving urgent medical attention in the street for what appeared to be a wound in his upper chest. Medics held an oxygen mask to his face while calling out for an ambulance.

Security forces on Saturday began employing rougher tactics, taking preemptive actions to break up protests and making scores, if not hundreds of arrests. Greater numbers of soldiers have also joined police. Many of those detained were taken to Insein Prison in Yangon’s northern outskirts, historically notorious for holding political prisoners.

According to the independent Assistance Association of Political Prisoners, as of Saturday, 854 people had been arrested, charged or sentenced at one point in relation to the coup, and 771 were being detained or sought for arrest. The group said that while it had documented 75 new arrests , it understood that hundreds of other people were also picked up Saturday in Yangon and elsewhere.

MRTV, a Myanmar state-run television channel, broadcast an announcement Saturday night from the Foreign Ministry that the country’s ambassador to the United Nations has been fired because he had abused his power and misbehaved by failing to follow the instructions of the government and “betraying” it.

Ambassador Kyaw Moe Tun had declared in an emotional speech Friday at the U.N. General Assembly in New York that he represented Suu Kyi’s “civilian government elected by the people” and supported the struggle against military rule.

He urged all countries to issue public statements strongly condemning the coup, and to refuse to recognize the military regime. He also called for stronger international measures to stop violence by security forces against peaceful demonstrators.

The junta said it took power because last year’s polls were marred by massive irregularities. The election commission before the military seized power coup had refuted the allegation of widespread fraud. The junta dismissed the old commission’s members and appointed new ones, who on Friday annulled the election results.

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