Russia-Ukraine updates: Putin suspends key US-Russia nuclear treaty in speech denouncing West

As President Volodymyr Zelenskyy travels to Washington, calls for the United States to take a larger role in the conflict are continuing.

The Institute for the Study of War called on Tuesday on the West, led by the United States, to stop expending resources trying to change a reality it does not control and instead focus on what it can shape plenty: Denying Russia’s ability to wage a war against Ukraine.

Instead of focusing on Russia's inflexible and maximalist intent in Ukraine, "the United States must help Ukraine liberate its territories and people through a large-scale counteroffensive or risk facing the same challenge with the same escalation risks under worse conditions," the ISW said, warning of the dangers of a Russian military foothold in Ukraine.

-ABC News’ Edward Szekeres

Plans are underway for Ukrainian President Volodymyr Zelenskyy to visit the U.S. Capitol on Wednesday, sources told ABC News.

The speech comes as the U.S. is set to announce a military aid package for Ukraine that includes Patriot air defense systems, U.S. officials told ABC News .

Zelenskyy previously addressed Congress via video on March 16, roughly three weeks into the war with Russia.

U.S. officials told ABC News that the next military aid package for Ukraine will be announced Wednesday and that it will include Patriot air defense systems and JDAM precision bomb kits.

-ABC News' Luis Martinez

More than 100,000 Russian soldiers battling in Ukraine have either been killed, reported missing or defected since the war began in February, according to estimates released Tuesday by British Defense Secretary Ben Wallace.

Marking the 300th day of the war, Wallace provided the update on Russia's war losses to the House of Commons in London. He also estimated that 4,500 Russian armored vehicles have been destroyed as well as 140 Russian helicopters and fixed wing aircraft.

The estimated losses by Russian forces are similar to what Ukrainian officials have released.

Wallace said the number of missions to Ukraine by the Russian Air Force have drastically declined from 300 a day in March to currently tens of missions per day.

He described Russia’s once powerful Black Sea fleet as "little more than a coastal defense flotilla."

In March, Russia occupied about 27% of Ukrainian territory, Wallace said. Since then, Ukraine liberated around 54% of the territory that has been taken since February.

He said Russia now controls roughly 18% of internationally recognized areas of Ukraine.

The Kremlin has yet to respond to Wallace's battlefield estimates.

Russia has failed to achieve any strategic objectives, Wallace said, adding that not one Russian operational commander who was in place at the start of the Russian invasion Feb. 24 remains.

Wallace also spoke about a deal between the Kremlin and Iran to supply Russia with more than 300 kamikaze drones.

"Iran has become one of Russia's top military backers," Wallace said.

He said that in exchange, Russia intends to provide Iran with advanced military components, undermining international security, particularly in the Middle East.

"We must expose that deal," Wallace said.