Myanmar’s military has warned anti-coup protesters across the country that they could face up to 20 years in prison if they obstruct the armed forces.
Long sentences and 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.
On Monday, Ms Suu Kyi’s lawyer said she would be detained for a further two days. She will then be tried via video link at a court in the capital Nay Pyi Taw on Wednesday, Khin Maung Zaw added.
Ms Suu Kyi was rounded up with other members of the government on 1 February, but her detention was due to end on 15 February, according to Reuters news agency.
The charges against her include possession of unlawful communication devices – walkie-talkies used by her security staff.
The military’s heightened presence is the latest sign of a potential crackdown on opposition to the coup. 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.
The ruling junta has also announced a series of legal changes, imposing long prison sentences and fines on anyone found to incite hatred towards the military, “by words, either spoken or written, or by signs, or by visible representation”.
In a statement posted on a military website on Monday, it said that people preventing the security forces from carrying out their duties could face 20 years in prison, while those found to stir up fear or unrest in public could be imprisoned for terms of three to seven years.
News of the legal threats came hours after the internet was restored following an overnight shutdown from Sunday into Monday.
As demonstrators gathered in the central city of Mandalay again on Monday, there were reports of security forces firing rubber bullets to disperse crowds.
In footage posted on social media, the sound of what appears to be gunshots can be heard as crowds flee, with several people later appearing to display injuries.
Police in the city were also reported to have used sling-shots against protesters and were met with volleys of bricks.
A leading student activist who has gone into hiding, Myo Ko Ko, told the BBC why he and others were willing to risk their lives.