YANGON (REUTERS, AFP) - Opponents of Myanmar's coup called on Monday (April 12) for people to show defiance of the military with costumes and prayers over the upcoming New Year holiday, hoping to maintain the momentum of their campaign in which more than 700 people have been killed.

The traditional New Year, known as Thingyan in Myanmar, is the most important holiday of the year and is usually celebrated with prayers, ritual cleaning of Buddha images in temples and high-spirited water throwing on the streets.

"The military council doesn't own Thingyan. The power of people is in the hands of people," Ms Ei Thinzar Maung, a leader of the General Strike Collaboration Committee protest group, wrote on Facebook.

"The people united need to hold a people's Thingyan," Ms Ei Thinzar Maung said.

She called for Buddhists to wear certain religious attire and to recite prayers together and for members of small Christian communities to wear white and read psalms. She said followers of other religions should follow the lead of their leaders.

The holiday runs from Tuesday to Saturday, which is New Year's Day.

Security forces have killed 706 protesters, including 46 children, since the military seized power from the elected government of Ms Aung San Suu Kyi in a Feb 1 coup, according to a tally by the Assistance Association for Political Prisoners (AAPP) activist group.

That included 82 people killed last Friday in the town of Bago - about 70km north-east of Yangon - which the AAPP called a "killing field".

There were reports on social media of shooting by the security forces in the north-western town of Tamu on Monday and of the police breaking up a protest in the city of Mandalay.

Details of the violence were difficult to obtain because of the junta's curbs on broadband Internet and mobile data services.

A spokesman for the junta could not be reached for comment.

The state-run Global New Light of Myanmar newspaper, in a report on the violence in Bago, said rioters armed with makeshift weapons had attacked security forces as they tried to clear protesters' barricades and one rioter was killed.

"Evidence of confiscated grenades and ammunition indicates small arms were used," said the newspaper, which has been a mouthpiece of the military for years.

Ms Suu Kyi, who has been detained since the coup, was hit with a fresh charge on Monday when she appeared by video link at a court hearing.

"Amay Suu has been charged again under section 25 of the natural disaster management law," lawyer Min Min Soe told AFP after the court hearing in the capital Naypyitaw.

"She has been charged in six cases altogether - five charges in Naypyitaw and one in Yangon."

The most serious charge Ms Suu Kyi faces falls under Myanmar's official secrets laws. A conviction could carry a prison sentence of up to 14 years.

She is also charged with violating coronavirus protocols, illegally possessing two-way radios and has been accused by the ruling military council of bribery.

Her lawyers say the charges were trumped up.