Here's What You Need To Know About The Ukraine Crisis Right Now

Russia invaded Ukraine on Thursday in the biggest attack by one state against another in Europe since World War Two.

Missiles rained down on its cities and residents fled after Russian President Vladimir Putin said his aim was to demilitarise and 'denazify' Ukraine.

Ukrainian and Russian forces fought along most of the border as Kiev reported invading troops pouring in from Russia and Belarus, and landing on its Black and Azov seas coasts.

NATO put more than 100 warplanes on alert. It will reinforce troops on its eastern flank but has no plans to deploy any in Ukraine, Secretary-General Jens Stoltenberg said.

Ukrainian President Volodymyr Zelenskiy urged citizens prepared to defend the country to come forward.

US President Joe Biden will meet with his Group of Seven counterparts Thursday to map out more measures against Russia after what he called its "premeditated war".

The European Commission said new EU sanctions will hit Russia's economy severely and erode its industrial base.

Central European countries started preparations to receive people fleeing Ukraine.

A mood of defiance gripped Kyiv even though the city echoed at times to the sound of gunfire, sirens and explosions and many people tried to leave.

European stocks plunged nearly 4%. Russia's rouble hit an all-time low.

UEFA will move the Champions League final from St Petersburg, a source said.

Who Said What

"I have decided to conduct a special military operation... to protect people who have been subjected to bullying and genocide," Russia's Putin said. "We will strive for the demilitarisation and denazification of Ukraine."

"Russia has embarked on a path of evil, but Ukraine is defending itself & won't give up its freedom," Ukraine's Zelenskiy said.

"Russia is using force to try to rewrite history... We have no plans to send NATO troops in Ukraine. What we do is defensive," said NATO Secretary-General Jens Stoltenberg said.

"The United States and our allies and partners will be imposing severe sanctions," Joe Biden said in a statement.

What's Next?

Biden to meet G7 counterparts.

Biden also convened his National Security Council.

EU leaders were discussing further sanctions on Thursday.

NATO will hold an emergency summit on Friday.

The U.N. Security Council will discuss a resolution condemning the invasion.

European Central Bank policymakers hold what may be a crisis meeting.