Ukraine recorded the "largest deterioration" of peace worldwide in the latest global peace report from the international think tank Institute for Economics & Peace.

"The war in Ukraine had a significant impact on global peacefulness, with Ukraine and Russia having the largest and fifth largest deteriorations in peacefulness respectively," the report stated.

Since last year's report, Ukraine fell 14 places to 157th among the 163 countries covered by the report. Due to the conflict, 65% of men in Ukraine ages 20-24 have fled the country or died, according to the report.

-ABC News' Emma Ogao

Ukrainian President Volodymyr Zelenskyy announced Wednesday the Security Service of Ukraine and the police arrested a suspect who they say coordinated with Russian forces in Tuesday's missile attack on Kramatorsk, a city in the Donetsk region.

The missiles struck a popular pizzeria and killed 12 people, including three children. More than 60 people were injured, the president said in a public address.

The unidentified "spotter" was charged with treason, according to Zelenskyy.

"Anyone in the world who does not understand that one cannot be an accomplice of a terrorist state must be held accountable by the entire international community," he said.

-ABC News' Will Gretsky

A senior U.S. official tells ABC News that Yevgeny Prigozhin thought he would have help from the Russian military.

Both former Russian military officers and some others in Moscow had conversations with Prigozhin before he started his march, the official said.

The U.S. doesn't believe Russian President Vladimir Putin realized this beforehand, and the officers sided with Putin in the end, the official said.

According to the official, Prigozhin was shocked he didn’t have support.

-ABC News' Martha Raddatz

Two Russian missiles struck Kramatorsk, a city in Ukraine's Donetsk region, killing at least four people, according to officials.

At least 47 people were injured in the attack, but the death and injury toll could rise.

One of the deceased victims was a 15-year-old and one of the wounded victims was a child under a year-old, officials said.

One missile struck an eatery downtown and the other one hit the outskirts of the city, Andriy Yermak the head of the Ukrainian Presidential Office said.

A restaurant and a hotel were badly damaged as a result of the strikes, according to officials.

Crews continued to dig through the rubble to search for victims throughout the evening.

"Each such manifestation of terror proves over and over again to us and to the whole world that Russia deserves only one thing as a result of everything it has done - defeat and a tribunal, fair and legal trials against all Russian murderers and terrorists," Ukrainian President Volodymyr Zelenskyy said in a statement.

-ABC News' Fidel Pavlenko and Ellie Kaufman

U.S. President Joe Biden will make a "memorable speech" before world leaders in Lithuania's capital on the final day of a high-stakes NATO summit, according to National Security Council Senior Director for Europe Amanda Sloat.

Biden's remarks on Wednesday afternoon will focus on similar themes to what he said during his speech in Poland in late February marking one year since Russia waged war on Ukraine.

"President Biden will talk about the strength of the NATO Alliance and how it remains a force for global security and stability, as it has for more than seven decades. He'll talk about how NATO is more vital to our shared future and that didn't happen by accident," Sloat told reporters during a press briefing in Vilnius on Wednesday morning.

"As the president has talked about before, Vladimir Putin thought he could break our resolve when he invaded Ukraine. But our NATO allies and our partners around the world responded by coming together to support the brave people of Ukraine as they defend their freedom, their independence and their democracy," she added.

Beyond addressing the strength of the NATO alliance and the importance of standing by Ukraine, Biden will also look to pitch cooperation like we've seen for Ukraine to tackle other major challenges facing the world, "including the climate crisis, emerging technologies, upholding the international rules of the road and expanding opportunities so we build an economy where no one gets left behind," according to Sloat.

-ABC News' Molly Nagle