Ukrainian President Volodymyr Zelenskyy spoke out against American critics who are pushing for cuts to military support to his country stating there are "dangerous voices" in Congress and in the U.S.

Zelenskyy told reporters Wednesday that his team was in constant contact with National Security Advisor Jake Sullivan and other U.S. national security officials, stating he was "glad" Ukraine had the backing of the White House, enjoyed bipartisan support in Congress and received “a lot” of support from the American public.

However, Zelenskyy said the coming year will be "very difficult," referring to the U.S. presidential election, which "will definitely have an impact on support for Ukraine."

"I think we’re going to have a hard time," Zelenskyy said.

He said the election results could be positive or negative for Ukraine.

“For our part, we will do everything to ensure that the support of the United States does not decrease…we will give all our time, our energy to constantly work with the USA," Zelenskyy said. “I expect that our partners in the United States will continue to be our partners and friends.”

Zelenskyy said Ukraine was working on lobbying Biden for longer range missiles.

-ABC News' Tom Buridge and Natalya Kushnir

The U.S. Department of Defense announced an additional $400 million aid package to Ukrainian forces that includes more weapons and ammunition.

This marks the Biden administration's 43rd military aid package to Ukraine since August 2021.

Some of the equipment and weapons in this package include, additional munitions for Patriot air defense systems and National Advanced Surface-to-Air Missile Systems (NASAMS); Stinger anti-aircraft systems and Javelin and other anti-armor systems and rockets.

-ABC News' Matthew Seyler

Ukraine has begun using the controversial cluster munitions that the U.S. recently began providing to Ukraine, a U.S. official confirmed to ABC News.

Ukraine, Russia and the U.S. are not signatories to the convention that bans the use of cluster munitions. Russia has used them in the war in Ukraine and so has Ukraine as they a supply of the weapons left over from the Soviet era.

"I believe they have started using them," Pentagon deputy press secretary Sabrina Singh said Thursday. "In terms of the effect on the battlefield, I'd really let Ukraine speak to how they intend to employ them. But you know, this is a powerful artillery that we have given them. They have ... committed to use it responsibly, to keep track and record where they are using it, so when this war is over, they can begin those de-mining efforts."

The weapons are considered dangerous to civilians because the small bomblets that are dispersed by the munitions can remain unexploded until someone accidentally stumbles upon them weeks, months or even years later.

-ABC News' Luis Martinez

Russian forces hit a three-story building and a garage in the city center of Mykolaiv Thursday morning, local time, injuring nine people, including five children, the Mykolaiv Regional State Administration said on Telegram.

There were fatalities stemming from the strikes, but it's unclear how many at this time, the Mykolaiv Regional State Administration added.

In another incident, Russian strikes hit Odesa early Thursday morning, the Odesa District Administration said on Telegram.

Two people were injured and hospitalized from the attack, according to the Odesa District Administration.

There is destruction "in the center" of Odesa and a fire broke out stemming from the strikes, the administration said.

-ABC News' Natalia Kushniir and Yuriy Zaliznyak

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