3 Latest Developments in the Invasion of Ukraine

What do you know as Putin alerts nuclear power ?!

Vladimir Putin has put his atomic powers on standby for expansion, in a marked acceleration of tension with the West since the collapse of the Soviet Union over Russia's attack on Ukraine.

A Ukrainian authority says road battles have broken out in Kharkiv, Ukraine's second largest city. For soldiers likewise, tensions increased at key ports in the south of the country after a flood of attacks on landing strips and fuel offices elsewhere appeared to limit another period of Russian involvement. (AP Photo / Efrem Lukatsky) Associated Press

Putin put his atomic forces on extended alert Sunday in an extraordinary acceleration of pressure with the West since the collapse of the Soviet Union over Russia's brutal systematic attack on Ukraine, which entered its fourth day of fighting in the ways of the second nation's largest city.

Here's what to learn about Russia's intervention in Ukraine and the security emergency in Eastern Europe:

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