Ukrainian President Volodymyr Zelensky has declared martial law across the country.

This comes following the “special military operation” announced by Russian President Vladimir Putin against Ukraine, while he was attending the UN Security Council meeting.

“Dear Ukrainian citizens, this morning President Putin announced a special military operation in Donbas. Russia conducted strikes on our military infrastructure and our border guards. There were blasts heard in many cities of Ukraine,” Zelensky said in a video message.

“We’re introducing martial law on the whole territory of our country. A minute ago, I had a conversation with President Biden. The US have already started uniting international support. Today each of you should keep calm. Stay at home if you can. We are working. The army is working. The whole sector of defense and security is working.”

He also appealed for calm amid the brewing tension. “No panic. We are strong. We are ready for everything. We will win over everybody because we are Ukraine,” he said.

The Ministry of Foreign Affairs of Ukraine announced that Russia has launched its full-scale invasion of the Eastern European Country.

“Putin has just launched a full-scale invasion of Ukraine. Peaceful Ukrainian cities are under strikes. This is a war of aggression. Ukraine will defend itself and will win. The world can and must stop Putin. The time to act is now,” Ukraine Foreign Minister Dmytro Kuleba said in a tweet.

UN chief Antonio Guterres told Putin condemned the ongoing invasion, saying: “In the name of humanity bring your troops back to Russia. In the name of humanity, do not allow a war to start in Europe which could be the worst war since the beginning of the century with consequences not only devastating for Ukraine, not only tragic for the Russian Federation but with an impact cannot even foresee.”

Explosions are being heard in several areas in Ukraine and near its capital.