Russian President Vladimir Putin announced a special military operation early on Thursday in eastern Ukraine’s Donbas region.

In a televised address, Putin said the people of Donbas turned to Russia for help, according to Russian news agency TASS.

“In this regard…I decided to conduct a special military operation,” he added.

Putin said the aim of the operation “is to protect people who for eight years have been suffering persecution and genocide by the Kyiv regime.”

“We will strive for the cleansing of Ukraine from Nazism and militarism, as well as bringing to justice those who committed a large number of bloody crimes against civilians, including citizens of the Russian Federation” he added.

Following Putin’s announcement, large explosions were reported in Ukraine’s capital Kyiv and the city of Kramatorsk.

Earlier, separatist leaders in eastern Ukraine had sought Putin’s help in repelling aggression from the Ukrainian army, the Kremlin announced late Wednesday.

NATO Secretary General Jens Stoltenberg on Thursday strongly condemned Russia’s “reckless and unprovoked attack on Ukraine”, saying it puts at risk countless civilian lives.

“Once again, despite our repeated warnings and tireless efforts to engage in diplomacy, Russia has chosen the path of aggression against a sovereign and independent country,” said Stoltenberg in a statement.

“This is a grave breach of international law, and a serious threat to Euro-Atlantic security. I call on Russia to cease its military action immediately and respect Ukraine’s sovereignty and territorial integrity,” said the NATO chief.

“NATO Allies will meet to address the consequences of Russia’s aggressive actions. We stand with the people of Ukraine at this terrible time. NATO will do all it takes to protect and defend all Allies,” he added.

Earlier on Wednesday UN Secretary-General Antonio Guterres made a direct plea to Russian President Vladimir Putin to not attack Ukraine.

“So, if indeed, an operation is being prepared, I have only one thing to say from the bottom of my heart: President Putin, stop your troops from attacking Ukraine,” said Guterres at a UN Security Council meeting requested by Ukraine.

“Give peace a chance. Too many people have already died,” he added.