Joe Biden, President of the United States, has condemned Russia’s “unprovoked and unjustified attack on Ukraine.

CNN reported that the US and its allies planned on Thursday to activate the penalties negotiated over the previous few weeks in retaliation for the assault.

“President Putin has chosen a premeditated war that will bring a catastrophic loss of life and human suffering,” Biden said in a statement Wednesday evening. “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.”

The White House statement came in response to explosions around Ukraine, including, Kyiv, the capital. Shortly before the explosions, Vladmir Putin, the Russian President, declared a “special military operation” and called for Ukraine’s “demilitarization” in broadcast statements.

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An assistant to the interior minister of Ukraine, Anton Gerashchenko, said Russia’s “invasion has begun” with “missile strikes on Kyiv,” in an official WhatsApp group chat with the media on Thursday.

According to a senior US official, the early judgment of the US is that this is the commencement of the Russian invasion. The source who spoke to CNN said explosions around Kyiv and Odessa were likely from missiles, and the ones around Kharkiv in eastern Ukraine were likely from artilleries because they were close to the border.

In a phone call with the Ukrainian President, Volodymyr Zelensky, Biden said he was taking steps to get the world’s attention.

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Biden indicated that he intended to talk to his G-7 colleagues and would deliver an address to the American people on Thursday.

He said he was going to talk about “further consequences” that the United States and its allies were going to give to Russia for “this needless act of aggression against Ukraine and global peace and security”.

“We will also coordinate with our NATO allies to ensure a strong, united response that deters any aggression against the alliance,” Biden said.

The US intends to target Russia’s two major banks, as well as other financial businesses, and has prepared to apply export restrictions to shut off Russian access to crucial western technologies for whole Russian economic sectors.

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Several more members of Vladimir Putin’s inner circle and their families are also expected to be targeted.

The person added that discussions were underway late Wednesday evening between US and European officials over the ultimate structure of the package. It will also be a subject of discussion in the virtual G-7 meeting that has been organised.

The US official said that US authorities are on the lookout for cyberattacks against important domestic targets like banks and critical infrastructure, and that they are on high alert.

Biden’s national security staff planned to update the House and Senate in separate, unclassified phone conversations Thursday on the situation in Ukraine. Lawmakers from both parties roundly blasted Russia’s conduct on Wednesday and asked for the US to beef up penalties against Moscow.