U.S. and world leaders rushed to condemn a Russian invasion of Ukraine on Wednesday night, warning of heavy sanctions to come for the attack announced in a televised addressed by Vladimir Putin.

Here's what some of those leaders said:

Lithuanian President Gitanas Nausėda

The Lithuanian President said only a united and strong response by democratic Western allies could stop Russia. 

"Never before have we been so strong & so well prepared to face external challenges together with our Allies," Gitanas Nausėda tweeted. The future of Europe "may depend on how we react in the coming hours & days." 

Ursula von der Leyen, President of the European Commission

"It is President Putin who was bringing war back to Europe. And in these dark hours, the European Union and its people stand by Ukraine and its people. We are facing an unprecedented act of aggression by the Russian leadership against a sovereign, independent country. Russia's target is not only Donbas, the target is not only Ukraine, the target is the stability in Europe and the whole of the International Peace order. And we will hold President Putin accountable for that."

German Chancellor Olaf Scholz

"The Russian attack on Ukraine is a blatant violation of international law. There is no justification for it. Germany condemns this reckless act by President Putin in the strongest possible terms. Our solidarity is with Ukraine and its people. 

Russia must stop this military action immediately. Within the framework of the G7, Nato and the EU, we will coordinate closely today. This is a terrible day for Ukraine and a dark day for Europe."

U.K. Prime Minster Boris Johnson

"I am appalled by the horrific events in Ukraine and I have spoken to President Zelenskyy to discuss next steps. President Putin has chosen a path of bloodshed and destruction by launching this unprovoked attack on Ukraine. The UK and our allies will respond decisively."

Finland President Sauli Niinistö

"I strongly condemn the military measures Russia has started in Ukraine. Russia's acts target Ukraine, but at the same time they are an attack on the entire European security order. We feel deep compassion towards Ukraine and are seeking ways to increase our support to Ukraine."

U.S. Rep. Adam Schiff, D-Calif., Chair of the House Intelligence Committee

“A massive Russian invasion of Ukraine has begun. There can be no certainty about what will come next, but no matter what the next days and weeks bring, the United States will stand with the people of Ukraine - now and always. This begins by moving swiftly beyond the significant sanctions already announced by the Biden administration to fully cutting off Russia’s leading financial institutions from the global economy and ending Europe’s dependence on Russian oil for good."

Sen. Mark Warner, D-Va., chair of the Senate Intelligence Committee

"While there is still an opportunity for Russia to reverse course, we can no longer hold out hope that this standoff can be resolved peacefully. Therefore, we must all, on both sides of the aisle and both sides of the Atlantic, work together to demonstrate to Putin that his aggression will not be allowed to go unpunished. 

"What is happening in Ukraine is a tragedy not only for Ukraine, but for the Russian people as well. They will pay a steep cost for Putin's reckless ambition, in blood and economic harm." 

NATO Secretary-General Jens Stoltenberg

"I strongly condemn Russia’s reckless attack on Ukraine, which puts at risk countless civilian lives. This is a grave breach of international law & a serious threat to Euro-Atlantic security. NATO Allies will meet to address Russia’s renewed aggression."

Linda Thomas-Greenfield, U.S. ambassador to the UN

“As President Biden said tonight, Russia alone is responsible for the death and destruction this attack will bring. And the United States and our allies and partners will respond in a united and decisive way. The world will hold Russia accountable."

Ukrainian Foreign Minister Dmytro Kuleba

"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."

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.

— Dmytro Kuleba (@DmytroKuleba) February 24, 2022

Sergiy Kyslytsya, Ukraine ambassador to the UN

"I asked the members or Security Council to convene an emergency meeting immediately and consider all necessary decisions to stop the war. Because it's too late, my dear colleagues, to speak about de-escalation. Too late."

Barbara Woodward, Britain’s ambassador to the UN

“This is a grave day for Ukraine and for the principles of the United Nations. We and our partners have been clear that there will be consequences for Russia's actions.”

Jens Stoltenberg, secretary general of NATO

"I strongly condemn #Russia’s reckless attack on #Ukraine, which puts at risk countless civilian lives. This is a grave breach of international law & a serious threat to Euro-Atlantic security. #NATO Allies will meet to address Russia’s renewed aggression."

Sen. Thom Tillis, R-NC

“May God Bless Ukraine and the Ukrainian people. Many will face unspeakable danger because of a corrupt and paranoid dictator who harbors grand ambitions of forming a new Soviet empire. America must stand in solidarity with Ukraine by providing financial support and military equipment. The Biden administration needs to quickly and significantly ramp up sanctions on Russia, and they need to hurt. Putin's regime must be held accountable for starting this unprovoked war against a free and sovereign democracy and spilling the blood of innocent people.”

UN Secretary-General Antonio Gueterres

"President Putin, in the name of humanity, bring your troops back to Russia. In the name of humanity, do not allow to start in Europe what could be the worst war since the beginning of the century."

Senate Democratic Whip Dick Durbin, D-Ill.

“Let me be clear: Vladimir Putin’s invasion of Ukraine’s sovereign land is a dire threat to the established international order and must be resolutely deterred.  Ukraine and our NATO allies facing ongoing Russian belligerence have strong bipartisan, bicameral support in the U.S. Congress. As someone who has strong ties to the region, my prayers are with the Ukrainian people and all of Eastern Europe.”

Ukraine Deputy Interior Minister Anton Gerashchenko

"The invasion has begun. There have just been missiles on the military headquarters, airports, military warehouses, near Kiev, Kharkov, Dnieper. Gunfire at the border is underway. A new geopolitical reality in the world from today."