YANGON (REUTERS) - Blasts from at least one parcel bomb in Myanmar have killed five people, including an ousted lawmaker and three police officers who had joined a civil disobedience movement opposing military rule, media reported on Tuesday (May 4).

Since the elected government led by Nobel laureate Aung San Suu Kyi was overthrown in a coup on Feb 1, Myanmar has seen an increasing number of small blasts in residential areas, and sometimes targeting government offices or military facilities.

The latest blasts were in a village in the southern central part of Myanmar in Western Bago and occurred at around 5pm on Monday, the Myanmar Now news portal reported, citing a resident.

Three blasts were triggered when at least one parcel bomb exploded at a house in the village, killing a regional lawmaker from Suu Kyi's National League of Democracy (NLD) party, as well as the three police officers and a resident, the report said.

Another police officer involved in the civil disobedience movement was also severely wounded after his arms were blown off by the explosion, the resident was cited as saying. He had been hospitalised and was receiving treatment, it said.

Khit Thit media also reported the blasts, citing an unnamed NLD official in the area.

Reuters could not independently verify the reports and a military spokesman did not answer a phone call seeking comment.

Violence has escalated since the coup, with hundreds reported killed by security forces, trying to quell pro-democracy protests in cities and rural towns. Ethnic militias have also backed opposition to the junta, and the military is fighting these groups on the fringes of Myanmar.

On Monday, the Kachin Independence Army, an ethnic rebel group, said it had shot down a military helicopter.

The Chinland Defence Force, a newly formed militia in Chin state bordering India, said on its Facebook page on Tuesday that its forces had killed at least four Myanmar army soldiers and wounded 10 in a clash overnight.

The Myanmar army has not commented on either claim so far.

Pro-democracy supporters held protests on Tuesday in the second-biggest city of Mandalay, including one by education staff calling for a boycott of schools and universities when they reopen in June, Myanmar Now reported.

In addition, anti-coup demonstrators marched in Kanbauk in southern Myanmar, photographs posted by Khit Thit Media showed.

The Assistance Association for Political Prisoners (AAPP) advocacy group says security forces have killed at least 766 civilians since the coup. The junta disputes the figure and says at least 24 members of security forces have been killed during the protests.

Reuters is unable to verify casualties because of the curbs placed on media by the junta. Many journalists are among the thousands of people who have been detained.

The junta has revoked the licences of a string of media groups since the coup including two news outlets in Kachin in recent days, Myitkyina News Journal and The 74 Media.

The junta said it had to seize power because its complaints of fraud in a November election won by Suu Kyi's party were not addressed by an election commission that deemed the vote fair.

Suu Kyi, 75, has been detained since the coup along with many other members of her party. The AAPP says more than 3,600 people are currently in detention for opposing the military.

Meanwhile, a leading Myanmar swimmer has called for an international boycott of his country's Olympic committee, branding it a "puppet" of the nation's military rulers.

Australia-based Win Htet Oo said he had given up his dream of swimming at the Tokyo Olympics in protest against the junta.

"I decided to reject any participation to the Tokyo Olympic Games under the auspices of the Myanmar Olympic Committee because I believe the Myanmar Olympic Committee is a puppet Olympic committee of the military regime in Myanmar which has been accused of genocide," Mr Win Htet Oo told Reuters in Melbourne on Monday.

"I believe that the Myanmar Olympic Committee as it is currently recognised should be expelled immediately from any international sporting events.

"What I'm doing is a small thing but I hope it can lead to lasting change in Myanmar."

Reuters was unable to reach the Myanmar Olympic Committee (MOC) for comment.

The 26-year-old swam for Myanmar at the 2019 South-east Asian Games in the Philippines where he posted an Olympic qualifying 'B' time in the 50 metres freestyle, which would allow him to compete at Tokyo on invitation by world swimming governing body Fina.

However, he said he had ruled himself out of selection as Myanmar's athletes would be used as "propaganda" by the military junta to legitimise their rule.

Mr Win Htet Oo swam for New York University at collegiate level before coming to Melbourne in 2017 to further develop his swimming. He now works as a lifeguard at the pool where he trains.

He said he had reached out to the International Olympic Committee (IOC) to raise his concerns about the situation in Myanmar but the IOC responded that they continued to recognise the MOC and would adhere to the IOC's principle of political neutrality.

The IOC told Reuters the MOC had recently "re-confirmed" that it was focused on the preparation of its Tokyo Olympic team and that any athlete that qualified would be selected.

"To the best of our knowledge, Mr Oo has not yet obtained a quota for the Olympic Games Tokyo 2020," the IOC said in a statement.

Mr Win Htet Oo hopes the IOC will reconsider and ban Myanmar from the Olympics. The Tokyo Games start July 23.

"At the very least I expect the IOC to send an investigative team to Myanmar if they can because I do have fears that many Myanmar athletes are being intimidated or threatened, to either participate in the Olympic Games or in international sporting events," he said.

"I don't wish to give out names but I know of many Myanmar athletes who have been outspoken against the military regime since the dictatorship took power."