Both pro- and anti-government protesters are camped out at different places in Bangkok after Thailand's army declared martial law "to restore law and order".
The army ordered the two groups to remain where they were and not march anywhere, in order to prevent clashes.
It is the 19th time in Thailand's history that the army has declared martial law.
The surprise move follows six months of street protests that have left the country without a proper functioning government, but the army denied that it was staging a military coup.
More top news
Mostly dry, calm and quiet
President Trump has signed proposals for regulations to "ban all devices" like bump stocks, which were used in the Las Vegas shooting.
The Prime Minister has been warned that she must make a decisive choice about what kind of trade deal she wants after Brexit.