Armored vehicles have appeared on the streets of several cities in Myanmar amid signs the military is preparing a crackdown on opposition to the coup it carried out on 1 February.
The internet was almost entirely shut down from 18:30 GMT (01:00 local time).
In the northern state of Kachin, the security forces fired shots at a protest - the ninth day of anti-coup demonstrations across the country.
A UN official accused the military of "declaring war" on the people. Tom Andrews, the UN special rapporteur on Myanmar (also known as Burma), said the generals were showing "signs of desperation" and would be held accountable.
Western embassies urged the military to show restraint.
A statement signed by the EU, the US and the UK said: "We call on security forces to refrain from violence against demonstrators, who are protesting the overthrow of their legitimate government."