At least two people protesting against last month’s military coup have reportedly been shot and killed by security forces on Tuesday after a morning of peaceful marches in parts of Myanmar.

Security forces have killed scores of their countrymen in recent days, and the UN has put the nationwide death toll at 149 since the February 1 coup that toppled Aung San Suu Kyi’s elected government.

The independent Assistance Association for Political Prisoners said 183 people have been killed since the coup.

Violence was reported on Tuesday in Myanmar’s biggest city, Yangon, where casualties have been the highest. Police used rubber bullets against crowds in several neighbourhoods, and one man was reported as shot dead.

Another killing was reported in Kawlin city in the north-western Sagaing region.

UN Human Rights Office spokeswoman Ravina Shamdasani said at least 11 people were killed on Monday, adding to 57 deaths over the weekend. While there were many more reports of killings, it was unable to corroborate them.

“The killing of demonstrators, arbitrary arrests and the reported torture of prisoners violate fundamental human rights and stand in clear defiance of calls by the Security Council for restraint, dialogue and a return to Myanmar’s democratic path,” UN secretary-general Antonio Guterres said in a statement.

State television MRTV announced on Tuesday evening that a leading figure in the Committee Representing Pyihtaungsu Hluttaw, comprising elected members of parliament who were not allowed to take their seats, has been charged with high treason, which carries a death sentence.

Dr Sasa – a medical doctor who uses a single name, is a member of the Chin ethnic minority and was appointed a special UN envoy by the CRPH – is accused of stirring up internal conflict and acting against the junta.

He is the public face of the Myanmar resistance in the international arena, even though he is reportedly in hiding.

The coup reversed years of slow progress towards democracy in Myanmar, which for five decades had languished under strict military rule that led to international isolation and sanctions.

Protesters in some areas have recently started to use tactics meant to avoid violent confrontations. On Tuesday, reports on social media said candlelit marches before sunrise were held in Mawlamyaing in Mon state in south-eastern Myanmar.

Another tactic has been to use signboards as proxies for human protesters, placing them in neat rows in public places. This tactic was reported to have been used by a group of engineers in the second-biggest city, Mandalay, in central Myanmar.

More conventional peaceful protests of the sort that have been occurring daily were held without incident on Tuesday in Monywa and Ye-U in central Myanmar, the city of Loikaw in the eastern state of Kayaw, and Kalaw in Southern Shan state, also in the east.

Complicating efforts to organise new protests as well as media coverage, mobile phone internet service was cut on Sunday night, although access was still available through fixed broadband connections.

Mobile data service had been used to stream live video coverage of protests, often showing security forces attacking demonstrators. It previously had been turned off only from 1am to 9am for several weeks, with no official explanation.

Sunday’s violence in Yangon — virtually all committed by police — led to the greatest single-day death toll since the coup. In its aftermath, Myanmar’s ruling junta declared martial law in a large part of the city.

The martial law announcements said that the junta, formally called the State Administrative Council, acted to enhance security and restore law and order, and that the Yangon regional commander has been entrusted with administrative, judicial and military powers in the area under his command.

The orders cover six of Yangon’s 33 townships.

The greatest violence and most deaths were reported in Yangon’s Hlaing Thar Yar township, an industrial area of many factories that supply the garment industry, a major export earner for Myanmar.

Several factories, many of which are Chinese-owned, were set on fire on Sunday by unknown parties, provoking the ire of Beijing.

Thousands of the township’s residents in cars, taxis, pick-up trucks, on motorcycles and on foot jammed roads out of the area on Tuesday.