Russian President Vladimir Putin announced the start of a military operation in eastern Ukraine early Thursday, saying he was acting in response to threats from Ukraine and warning other countries not to intervene.

He added in the televised address that those who oppose the Russian action in the Donbas region will face “consequences they have never seen."

Around the same time, several rumbling explosions were heard in Ukraine’s capital, Kyiv, away from the city center.

U.S. President Joe Biden said in a statement that the people of Ukraine were suffering “an unprovoked and unjustified attack by Russian military forces.”

“President Putin has chosen a premeditated war that will bring a catastrophic loss of life and human suffering,” Biden said. “Russia alone is responsible for the death and destruction this attack will bring, and the United States and its Allies and partners will respond in a united and decisive way. The world will hold Russia accountable.”

Biden said that after speaking with G-7 leaders Thursday morning, he will announce “the further consequences the United States and our Allies and partners will impose on Russia for this needless act of aggression against Ukraine and global peace and security.”

The United States and other Western allies of Ukraine imposed a series of sanctions earlier this week against Russian officials and the country’s financial system, and halted a Russian gas pipeline project, warning that further Russian action in Ukraine would trigger harsher measures.

Ukrainian Foreign Minister Dmytro Kuleba, who on Wednesday said more sanctions were urgently needed to stop further aggression from Putin, tweeted Thursday that the Russian leader had launched “a full-scale invasion of Ukraine."

“Peaceful Ukrainian cities are under strikes. This is a war of aggression,” Kuleba posted. “Ukraine will defend itself and will win. The world can and must stop Putin. The time to act is now."

NATO Secretary General Jens Stoltenberg condemned Russia’s attack, calling it a “grave breach of international law.”

“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,” Stoltenberg said in a statement. “I call on Russia to cease its military action immediately and respect Ukraine’s sovereignty and territorial integrity. 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.”

Putin’s remarks came a short time after U.N. Secretary-General Antonio Guterres pleaded during an emergency meeting of the U.N. Security Council for Putin to avoid the conflict.

“Tonight, I have only one thing to say, from the bottom of my heart: President Putin, stop your troops from attacking Ukraine. Give peace a chance. Too many people have already died,” Guterres said.

Another sweeping cyberattack struck Ukrainian government websites Wednesday, as the Pentagon said Russian forces were closing in on Ukraine’s borders, readying “to conduct military action” “at virtually any time now.”

“We believe that they are, they’re ready," Pentagon press secretary John Kirby told reporters Wednesday.

Kirby said the Pentagon believes “additional Russian military forces are moving into” the Donetsk and Luhansk regions of Ukraine, but he would not confirm specifics on the number of Russian troops that have moved into these two regions.

VOA has not independently confirmed the presence of additional Russian troops in the Donbas.

Kremlin spokesperson Dmitry Peskov told Russian state media the heads of the self-proclaimed Donetsk People’s Republic and Luhansk People's Republic had asked Putin for help Wednesday in fighting Ukrainian armed forces.

Kirby would not attribute the latest cyberattack to Russia, only saying that disruptions in cyberspace were “of a Russian playbook.” Kyiv blamed Moscow for the cyberattacks, although Russia has denied any involvement.

A senior defense official told reporters earlier Wednesday that as many as 80% of the more than 150,000 Russian troops surrounding Ukraine were in “forward positions ready to go,” including troops on more than 10 landing ships in the Black Sea.

Ukrainian President Volodymyr Zelenskyy addressed his nation late Wednesday night.

“The people of Ukraine and the government of Ukraine want peace,” he said in Russian, hours after declaring a nationwide state of emergency. If the nation comes under an attack, “we will fight back,” he said.

He went on to reject Russia’s claims that Ukraine is a threat and said an invasion would cost thousands of lives.

He also said he tried to call Putin, but there was no answer from the Kremlin.

Earlier this week Putin decreed the eastern Ukraine regions of Luhansk and Donetsk were independent states. Putin also said he was sending what he characterized as “peacekeeping forces” across the Ukrainian border, stoking fears of a broader conflict with the one-time Soviet republic, which has been independent since 1991.

The Ukrainian Foreign Affairs Ministry advised against travel to Russia and urged anyone there to leave immediately, contending that Moscow’s “aggression” could curb its ability to provide consular services.

Russia began evacuating its diplomatic posts in Ukraine and by Wednesday afternoon the Russian flag was no longer flying over its embassy in Kyiv, where police surrounded the building. (VOA)

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