The Myanmar military warned to jail anti-coup protesters for up to 20 years if they obstruct the armed forces.
Apart from long sentences fines will also apply to those found to incite “hatred or contempt” towards the coup leaders, the military said.
Hundreds of thousands of people have taken part in protests in recent days.
The demonstrators are demanding the release from detention of their elected leaders, including Aung San Suu Kyi, and the restoration of democracy in Myanmar, also known as Burma.
The military government on Saturday gave itself power to make arrests, carry out searches and hold people for more than 24 hours without a court ruling.
It has also told journalists not to describe the military’s takeover as a coup.
The legal changes were announced as armoured vehicles appeared on the streets of several cities. At many strategic locations, soldiers have replaced the police.
In the main city, Yangon, eight-wheeled armoured vehicles have been seen trying to navigate the rush-hour traffic, sometimes surrounded by cars honking their opposition to the coup.
Protests focused on the central bank building, the US and Chinese embassies, and the city headquarters of Ms Su Kyi’s National League for Democracy.
Last week, the military released thousands of prisoners to deal with prison overcrowding.
Military Justify Coup:
The coup took place as a new session of parliament was set to open. The military declared a year-long state of emergency and handed over power to Commander-in-chief Min Aung Hlaing.
In the November 8 general elections, Aung San Suu Kyi’s party, NLD won 83% of available seats. But the military disputed the election results.
The fears of coup rose after the election commission rejected the military’s allegations of fraud elections.
This was just the second election since the end of military rule in 2011.