ALSO SEE: The Grim Reality of War Hits Stunned Ukrainians

The president was expected to lay out "further consequences" for Moscow in remarks on Thursday, including additional sanctions.

President Joe Biden is expected to announce “further consequences” for Russia in a speech at the White House on Thursday afternoon, just hours after Moscow launched an attack against Ukraine, plunging Europe into one of its gravest security crises since World War II.

As explosions erupted in cities across Ukraine, Biden accused Russian President Vladimir Putin in a statement Wednesday night of choosing “a premeditated war that will bring a catastrophic loss of life and human suffering.”

“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.

Biden announced a narrow round of sanctions against Russia on Tuesday after Putin moved troops into Moscow-backed breakaway regions in the eastern part of Ukraine, hoping to deter the Russian leader from launching a large-scale invasion of Ukraine.

The president warned then that more severe actions would be taken against Russia if Putin were to escalate the situation.

“Russia will pay an even steeper price if it continues its aggression, including additional sanctions,” Biden said Tuesday.

The initial tranche of sanctions include penalties against two Russian banks and Russian elites with close ties to Putin, and prohibited Russia from trading debt in American or European markets. The Biden administration on Wednesday also moved ahead with sanctions against the company in charge of constructing the controversial Nord Stream 2 gas pipeline.

Biden spoke to President Volodymyr Zelenskyy of Ukraine and updated him on the steps that the U.S. and its partners were taking to “rally international condemnation.”

“He asked me to call on the leaders of the world to speak out clearly against President Putin’s flagrant aggression, and to stand with the people of Ukraine,” Biden said.

Biden met with his National Security Council Thursday morning in the Situation Room. He was also scheduled to meet virtually with Group of Seven leaders to discuss the situation in Ukraine.