Wow this is first time Putin faces a serious internal crisis.

What's been happening in Russia?
Things have been developing quickly in Russia.

Here's what has happened in the past few hours.

President Putin made a televised speech calling the challenge by the Wagner mercenary force "high treason" and a "stab in the back". He appealed for unity and said authorities were acting quickly to contain the situation
Rebelling Wagner mercenaries say they have taken control of the Russian city of Rostov-on-Don, a key military site.
BBC sources also say Wagner forces have now seized military facilities in a second city - Voronezh, which is halfway between Rostov-on-Don and Moscow.
Prigozhin has said he will march on the capital if top military figures don't meet with him.
Prigozhin appears to have responded to Putin in an audio message, saying his troops were not committing treason, but rather were "patriots" fighting for the future of the Motherland - calling out "corruption, lies and bureaucracy"
And the international community is starting to respond. Some countries that border Russia are building up security, while NATO says it is monitoring the situation closely.