Former Vice President Mike Pence and his wife, Karen, crossed the Polish border into Ukraine to meet with refugees on Thursday, an aide told ABC News.

The Pences were in Poland on a humanitarian visit with the evangelical aid organization Samaritan's Purse, the aide said. They were in Ukrainian territory for about an hour.

When White House press secretary Jen Psaki was asked Thursday whether the Biden administration knew Pence was going to be at the Ukrainian border today, she responded that she would check.

Pence's team had not been in contact with the U.S. government regarding the trip "because he was there for humanitarian purposes," with Samaritan's Purse, the aide told ABC News.

Vice President Kamala Harris was also in Warsaw, Poland, on Thursday to demonstrate U.S. support for NATO's eastern flank allies.

-ABC News' Ben Gittleson

Around 15,000 civilians were evacuated from Ukrainian cities Thursday through humanitarian corridors that were operational, without major ceasefire violations reported, according to Ukrainian officials. However, no civilians have been evacuated from Mariupol, nor have humanitarian supplies been delivered into the city.

From the Sumy region, more than 12,000 civilians were evacuated using 54 buses and 2,664 private vehicles, according to Ukraine's State Emergency Services.

Around 1,200 people were evacuated from Izyum on Thursday, according to Kharkiv's regional governor.

According to the Kyiv Region Police Department, 2,000 civilians were evacuated from Bucha and Irpin to Kyiv.

Irina Vereschuk, the deputy prime minister in charge of reintegration and temporarily occupied territories, said on Thursday that what's happening in Mariupol is "beyond a humanitarian disaster."

According to Vereschuk, Mariupol currently does not have power, gas or heat and there is very little communication with the outside.

Vereschuk said they had hoped it would be possible to get humanitarian supplies into and some civilians out of Mariupol, but heavy shelling and air bombardment has continued, so that has not been possible.

According to Vereschuk, there is an International Committee of the Red Cross humanitarian convoy in Zaporizhzhia that departs to Mariupol daily to deliver aid, including water, basic food supplies and medicine, but it is constantly forced to turn back.

Nearly all roads leading out of Mariupol have been destroyed, with only two remaining routes out of the city still intact and Ukrainian authorities are still trying to contact the appropriate Russian authorities to agree on a ceasefire, according to Vereschuk.

An ICRC convoy with humanitarian supplies arrived on Thursday in the southern Ukrainian city of Energodar, but a planned evacuation of residents by private transport had to be postponed to Friday morning after the shelling resumed, the city's mayor said.

-ABC News' Christine Theodorou

Inflation rates in coming months will be higher than they would have been had Russia not invaded Ukraine, White House press secretary Jen Psaki said Thursday.

When asked by ABC News White House correspondent Mary Bruce how high the Biden Administration expects inflation rates to climb, Psaki said the energy and fuel prices will go up, but the increase will be "temporary and long-lasting."

While inflation rates are expected to decrease by the end of the year, "There is also no question that inflation may be higher for the next few months than it would have been without the Russia," Psaki said.

"What our focus is on now is doing everything we can to mitigate and reduce those prices and ensure there isn't a longer-term impact," Psaki said. "So I can't make new projections for you from here other than to convey that, yes, it is accurate that the invasion by President Putin into Ukraine has impacted global inflation, inflation in the United States, because of the impact it's had on energy prices -- and that is a significant contributor to inflation."

-ABC News' Molly Nagle

President Joe Biden spoke to Turkish President Recep Tayyip Erdogan Thursday to discuss the Russian invasion of Ukraine, after Turkey hosted talks between Russia and Ukraine's foreign ministers.

"President Biden expressed appreciation for Turkey’s efforts to support a diplomatic resolution to the conflict, as well as Turkey’s recent engagements with regional leaders that help promote peace and stability," the White House said in a statement.

The two leaders also discussed opportunities to strengthen their bilateral ties. In a press briefing, White House Press Secretary Jen Psaki said the call was "constructive" and confirmed it was lengthy, lasting around an hour or more.

"It is important that [Turkey] is in a facilitator position in search for a solution, in case the Russia-Ukraine crisis deepens further," Erdogan told Biden, according to Turkey's Anadolu, a state-run news agency.

"Even organizing a tripartite meeting of foreign ministers of [Turkey], Russia, and Ukraine in Antalya is a diplomatic victory by itself," he told Biden, according to the news service.

According to Anadolu, Erdogan also told Biden "it is time to lift all unjust sanctions" on Turkey's defense industry.

-ABC News' Christine Theodorou and Molly Nagle

The tower that provides the main signal to TV and radio in Kyiv has been struck by a Russian missile, leaving at least five dead, Ukrainian officials said.

Ukraine's Foreign Minister Dmytro Kuleba tweeted that the tower "is situated on the territory of Babyn Yar. On September 29-30, 1941, Nazis killed over 33 thousand Jews here. 80 years later, Russian Nazis strike this same land to exterminate Ukrainians. Evil and barbaric."

Ukraine's President President Volodymr Zelenskyy tweeted, "What is the point of saying «never again» for 80 years, if the world stays silent when a bomb drops on the same site of Babyn Yar? At least 5 killed. History repeating."

-ABC News' Christine Theodorou