YANGON, Myanmar (AP) — Authorities in Myanmar arrested the country’s best-known comedian on Tuesday as they continue to crack down on people they accuse of helping incite nationwide protests against February’s military coup.

The comedian Zarganar was taken from his home in Yangon by police and soldiers who arrived in two army vehicles, fellow comedian Ngepyawkyaw said on his own Facebook page. Zarganar, 60, is a sharp-tongued satirist who has been in and out of prison since he was active in a failed 1988 popular uprising against a previous military dictatorship. He is also well known for his social work, especially arranging assistance for victims of Cyclone Nargis in 2008.

In the past week, the junta has issued arrest warrants for about 100 people active in the fields of literature, film, theater arts, music and journalism on charges of spreading information that undermines the stability of the country and the rule of law. It was not immediately clear what Zarganar, whose real name is Maung Thura, has been charged with.

Many ordinary protesters and activists are also being arrested every day, according to numerous reports on social media.

In Mandalay, the country’s second-biggest city, security forces used stun grenades and fired guns Tuesday to break up a march by medical workers who have defiantly continued to protest almost every day against the Feb. 1 coup that ousted the elected government of Aung San Suu Kyi. The army’s takeover set back Myanmar’s gradual return to democracy after five decades of military rule.

A participant who asked to remain anonymous for his own safety told The Associated Press that doctors, nurses and medical students were attacked as they gathered at about 5 a.m. by security forces who also used cars to run into protesters on motorbikes. The online news site The Irrawaddy reported that four doctors were arrested.

At least 570 protesters and bystanders, including 47 children, have been killed in the crackdown since the takeover, according to the Assistance Association for Political Prisoners, which monitors casualties and arrests. The group says 2,728 people, including Suu Kyi, are in detention.

U.N. spokesman Stephane Dujarric said U.N. officials in Myanmar are “deeply concerned” about the impact of the continuing violence on the country’s health system, pointing to at least 28 attacks against hospitals and health personnel since Feb. 1. And they are also concerned at violence against the education system, pointing to 7 attacks against schools and school personnel since the coup, he said.

“Health volunteers are attacked, and attacks against ambulances are preventing life-saving help reaching civilians wounded by security forces,” Dujarric said.

Activists have begun organizing a boycott of next week’s official celebration of Thingyan, the country’s traditional New Year, usually a time for family reunions and merry-making.

In leaflets and social media posts, they are imploring people not to hold any Thingyan celebrations, saying it would be disrespectful to “fallen martyrs” to enjoy the festival.

The leaders of Brunei and Malaysia announced Monday that leaders of the Association of Southeast Asian Nations will meet to discuss the situation in Myanmar.

No date was given in the announcement, issued during a visit by Malaysian Prime Minister Muhyiddin Yassin to Brunei. He and Sultan Hassanal Bolkiah said they “expressed serious concern on the ongoing crisis in Myanmar and the rising number of fatalities.” Indonesian President Joko Widido had proposed a summit on Myanmar last month.

There was no word on whether the ASEAN leaders would participate in person or by video, or if Myanmar, one of the group’s 10 members, would attend.

Myanmar’s junta also has been battling in some border areas where ethnic minority groups maintain their own armed forces. Several major groups, most notably the Karen and the Kachin, have expressed solidarity with the anti-coup movement and vowed to protect protesters in the territory they control.

The Kachin in the country’s north have engaged in combat with government forces, but the Karen in the east have borne the brunt of the junta’s military assaults.

The area where the Karen National Union holds sway has been subject to air attacks by the Myanmar military from March 27 through Monday, said David Eubank of the Free Burma Rangers, a humanitarian organization that has for many years provided medical assistance to Karen villagers. Burma is another name for Myanmar.

Eubank said his group has verified that 14 civilians died and more than 40 were wounded in the air strikes. He said Tuesday that Myanmar’s military is mounting a ground offensive into Karen territory, driving villagers from their homes and increasing the number of displaced people in the area to more than 20,000, many of whom have to hide in caves or the jungle and are in desperate need of food and other necessities.

“The situation now seems, from our perspective, to be all-out war to the finish,” Eubank wrote Monday in an emailed message. “Unless there is a miracle, the Burma Army will not hold back in their attempt to crush the Karen and any other ethnic group that stands against them, just as they have not held back killing their own Burman people in the cities and plains of Burma.”