Small groups of protesters have begun to gather in Myanmar, despite the armoured vehicles which have appeared on the streets of several cities.
Hundreds of thousands of people have taken part in protests over the last 10 days, demanding democracy be restored.
They also want their elected leaders released from detention.
But on Monday, it was reported civilian leader Aung San Su Kyi would be detained for a further two days, according to her lawyer, Khin Maung Zaw,
She was rounded up with other members of the government in the early hours of 1 February, but her detention was due to end today, news agency Reuters said.
Her party was elected in a resounding victory last November, but the military has alleged voter fraud without providing proof.
The news came hours after the internet was restored. Telecoms operator said they had been told to shut off services from 01:00 to 09:00 local time, Sunday into Monday (
18:30 to 02:30 GMT).
Internet traffic was at 14% of normal levels after the order came into force, according to NetBlock, a monitoring group.
What are the signs of a crackdown?
Across the country on Sunday, hundreds of thousands of protesters rallied against the military for the ninth day in a row.
In the city of Myitkyina, in Kachin state, shooting could be heard as security forces clashed with anti-coup demonstrators. It was not clear whether rubber bullets or live rounds were being fired.
Five journalists were among those arrested.
In Yangon, armoured vehicles were seen on the streets for the first time since the coup. Monks and engineers led a rally there, while motorcyclists drove through the streets of the capital, Nay Pyi Taw.
A doctor at a hospital in Nay Pyi Taw told the BBC the security forces were carrying out night-time raids on homes.
“I’m still worrying because they make a curfew statement just not to go outside between 20:00 and 04:00, but this makes a time for the police and soldiers to arrest people like us,” said the doctor, who cannot be named for safety reasons.
“The previous day they stole into the house, cut down the fence, entered and arrested people unlawfully. That’s why I’m also worrying.”
An office of the US embassy in Yangon warned US nationals to stay indoors during curfew hours.
On Saturday, the military said arrest warrants had been issued for seven prominent opposition campaigners and warned the public not to harbour opposition activists fleeing arrest.
Video footage showed people reacting with defiance, banging pots and pans to warn their neighbours of night-time raids by the security forces.
The military on Saturday also suspended laws requiring court orders for detaining people longer than 24 hours and for searching private property.