Peace talks have been grinding on for months, with little visible progress toward a deal to end the war in eastern Europe.

Poland and Romania scrambled Nato fighter jets early on Wednesday as a series of explosions rang out across western Ukraine. In Poland, two airports in its southeast were shut down as Russian airstrikes targeted the cities of Lviv and Ternopil. The Polish military said it was forced to act to ensure the safety of Polish airspace.

At least 20 people were killed and many more wounded in the western city of Ternopil when a missile hit a residential building, the authorities there said.

At least 10 people were killed and 37 injured, including 12 children, during a large Russian strike on the city of Ternopil in western Ukraine, said Igor Klymenko, Ukraine's minister of internal affairs. He said the western regions of Lviv, Ivano-Frankivsk, and Ternopil were "under a massive enemy attack" on Wednesday.

The U.S. Army’s top two leaders will arrive in Ukraine this week for unannounced high-level talks expected to focus on boosting efforts to negotiate an end to the country’s war with Russia.

Ukraine has asked the Vatican to formalize its role facilitating negotiations for the return of Ukrainian children and civilians taken by Russia during the war

Russian lawmakers have endorsed new tax hikes as Moscow tries to boost its economy during its almost four-year war with Ukraine.

Elsewhere, the president of Finland warned that a ceasefire in Ukraine is unlikely before the spring and urged European allies to keep up support.

Immigration lawyers say those deported to Ukraine could be conscripted to fight in the war, contrary to international laws that prohibit deportations to places where people could face violence.

As Russia's war in Ukraine continues, Estonian Foreign Minister Margus Tsahkna spoke with NBC News' Joe Fryer and Savannah Sellers about the importance of NATO members standing together in the face of Russian aggression and hoped that a peace plan could still happen.