Russia-Ukraine updates: US sanctions Russian military shipbuilder, diamond miner

Russia’s military forces are “struggling to overcome” Ukraine’s terrain as they attempt to push further into the country, the U.K. Ministry of Defence said on Wednesday.

“Russian forces have remained largely tied to Ukraine’s road network and have demonstrated a reluctance to conduct off-road manoeuvre,” the Ministry said in an update. “The destruction of bridges by Ukrainian forces has also played a key role in stalling Russia’s advance.”

Ukraine’s military has “adeptly exploited” Russia’s difficulty moving through the country, “frustrating the Russian advance and inflicting heavy losses on the invading forces,” the update said.

-ABC News’ Zoe Magee

President Joe Biden is planning to announce $800 million in new military assistance to Ukraine on Wednesday, according to a source familiar with the matter.

The new assistance includes anti-armor and anti-aircraft weapons, the source told ABC News.

The funding is part of a $13.6 billion aid package to Ukraine that was included in the $1.5 trillion government spending bill that Biden signed into law Tuesday.

The law designates that $3.5 billion of the Ukrainian aid package go toward weapons, but leaves the exact military equipment and weaponry up to the administration. Biden is expected to provide more details Wednesday on how the $800 million will be spent.

-ABC Chief White House Correspondent Cecilia Vega, Molly Nagle, Ben Gittleson and Benjamin Siegel

After meeting with the prime ministers of Poland, the Czech Republic and Slovenia in Kyiv on Tuesday, Ukrainian President Volodymyr Zelenskyy said that the European Union leaders took a "courageous, right" step.

"They are not afraid of anything. And they are more afraid for our fate. And they are here to support us," Zelenskyy said in a video posted to Facebook.

"We absolutely trust these friendly countries," he later said.

The leaders -- Czech Prime Minister Petr Fiala, Slovenian Prime Minister Janez Jansa and Polish Prime Minister Mateusz Morawiecki, as well as Polish Deputy Prime Minister Jaroslaw Kaczynski -- traveled to the Ukrainian capital on a European Union mission to show support for the country.

In another video, Zelenskyy said their visit was a "strong sign of support."

The meeting's "top agenda" was "international assistance and reconstruction of Ukraine," according to Ukrainian Prime Minister Denys Shmyhal.

The leaders are working together “to ensure that the funds & property of the Russian Federation will be paid to Ukraine to restore everything destroyed by [the Russian] aggressor," he said on Twitter.

-ABC News' Matt Foster

The U.S. will provide an additional $186 million in humanitarian assistance to support Ukrainians displaced by the war, including those in the country and refugees who have fled, Secretary of State Antony Blinken announced Tuesday.

The funding, which brings the total U.S. assistance since the invasion began to $293 million, will support "food, safe drinking water, protection, accessible shelter and emergency health care," he said in a statement.

The U.S. State Department and the U.S. Agency for International Development are not directly providing this assistance but are working through international and nongovernmental partners.

Russian bombardment and shelling continue to damage roads, bridges and railroads in Ukraine, making it difficult for aid workers to reach people in need, according to a senior administration official, who warned the situation is "rapidly getting worse."

-ABC News' Conor Finnegan