What happened this week in Ukraine: Key events explained in 5 graphics

Tensions escalated between Russia and the rest of the world as Ukraine continued to receive aid while Russian President Vladimir Putin weaponized natural gas supplies amid claims that Russian troops were trying to to "starve out" Ukrainians. 

There were also attempts to hit back at Russia through attacks on the Transnistria region of Moldova, which sits at Ukraine's border, while President Joe Biden asked Congress to approve additional aid to Ukraine and Sweden and Finland made plans to join NATO. 

Here's what happened this week. 

Russia launches attack in Kyiv after Zelensky and UN chief meeting

Russian missiles struck Ukraine's capital of Kyiv Thursday evening, barely an hour after a meeting between Ukrainian President Volodymyr Zelenskyy and U.N. Secretary-General António Guterres. Several people were injured and at least one person was killed in the attack. 

Zelenskyy condemned the attack in a video address, stating that "This says a lot about Russia’s true attitude toward global institutions, about the efforts of the Russian leadership to humiliate the U.N. and everything that the organization represents." 

Explosions target Transnistria

The Russian-aligned Transnistria region of Moldova, which lies at the Ukrainian border, was rocked by explosions earlier this week. The initial explosions Monday night targeted the headquarters of the Russian-paid Transnistria security forces. Additional explosions Tuesday destroyed transmission towers used for Russian broadcasts. 

Monday's explosions were caused by grenade launchers, according to Moldovan officials. They also said that the attacks were designed "to create pretexts for tensioning the security situation" in the disputed area. 

►In-depth reporting:Transnistria is just a sliver of land between Moldova and Ukraine. But it's becoming a focus of war.

Biden asks Congress for $33 billion in aid for Ukraine

Biden asked Congress to approve $33 billion in security, economic and humanitarian aid to Ukraine Thursday, which includes $20.4 billion in security and military assistance as well as U.S. efforts to strengthen European security. 

About $8.5 billion of Biden's requested aid package would help Ukraine provide food, energy and health care as well as additional basic services to Ukrainians as the country continues to fend off Russian troops. An additional $3 billion would be used to provide wheat and other goods to people in need as a way to address food security around the world.   

►Daily recap:White House seeks quicker sale of mega-yachts, other seized Russian assets; Russia strikes Kyiv while UN head visits

Russia shuts off gas supply to Poland, Bulgaria

Russia announced Wednesday it would be shutting off gas supplies to Poland and Bulgaria, two European Union nations that have backed Kyiv during the war. The move came just one day after the United States and other allies announced plans to increase military support to Ukraine. 

Gazprom, a state-controlled Russian giant, later said it cut natural gas deliveries into the two nations and would do so until payments are made in Russian rubles, according to demands by Putin. European Commission President Ursula von der Leyen, referred to the move as "blackmail."  

►Impact at home:US diesel fuel prices could top $6 after Russia's moves against Poland and Bulgaria

Sweden and Finland will apply to join NATO, reports say

Media outlets in both Sweden and Finland are reporting that their governments will apply to join NATO next month in response to Russia's brutal invasion into Ukraine and as support for membership has grown in both countries. 

NATO has provided Ukraine with support since the start of the war, despite it not being a member of the alliance. 

Concerning conditionsin port city of Mariupol

Ukrainian officials in the port city of Mariupol continued to share the dire conditions civilians are currently facing, calling for immediate evacuation for those remaining. 

Mayor Vadym Boychenko referred to the living conditions as "medieval," and the city council warned that diseases, including cholera and dysentery, could break out since the city has no central water or sewage and as bodies are decaying under the rubble. 

More coverage of Russia's war in Ukraine from USA TODAY