President Joe Biden is nominating Bridget Brink to serve as U.S. ambassador to Ukraine, he announced Monday.

Brink is currently the U.S. ambassador to the Slovak Republic and previously served as senior adviser and deputy assistant secretary in the State Department's Bureau of European and Eurasian Affairs.

"Brink spent her twenty-five-year career in the Foreign Service focused on advancing U.S. policy in Europe and Eurasia," Biden's statement said.

U.S. Secretary of State Antony Blinken on Monday said Russia had "already failed" to achieve its stated goals in Ukraine.

"In terms of Russia's war aims, Russia has already failed," Blinken told reporters in Poland, near the Ukrainian border. "And Ukraine has already succeeded because the principal aim that President Putin brought to this, in his own words, was to fully subsume Ukraine, back into Russia to take away its sovereignty and independence. And that has not happened and clearly will not happen."

Blinken and U.S. Secretary of Defense Lloyd Austin met on Sunday with Ukrainian officials in Kyiv, the capital, becoming the highest-level U.S. officials to visit the war-torn country since Russia invaded in February.

Topics discussed during their three-hour meeting included defense assistance, further sanctions on Russia and financial support for Ukraine, according to Ukrainian President Volodymyr Zelenksyy's office.

"We appreciate the unprecedented assistance of the United States to Ukraine," Zelenskyy said, according to his office. "I would like to thank President Biden personally and on behalf of the entire Ukrainian people for his leadership in supporting Ukraine, for his personal clear position."

He added, "To thank all the American people, as well as the Congress for their bicameral and bipartisan support. We see it. We feel it."

The United States will provide Ukraine with $322 million in new aid and some diplomats will return to the war-torn country, U.S. Secretary of State Antony Blinken and U.S. Defense Secretary Lloyd Austin told Ukrainian President Volodymyr Zelenskyy in Kyiv on Sunday.

Blinken told Zelenskyy the U.S. would begin returning its diplomats to Ukraine this week, according to the senior State Dept. official. The U.S. will reopen offices in Lviv in western Ukraine, with diplomats traveling there from Poland each day, with the goal to "have our diplomats return to our embassy in Kyiv as soon as possible."

President Joe Biden will also formally nominate Bridget Brink, currently serving as U.S. ambassador to Slovakia, to serve as the U.S. ambassador to Ukraine, according to the senior State Dept. official.

Among the new assistance announced last week, the first of the new Howitzers have arrived in Ukraine, Austin told Zelenskyy, a senior defense official told ABC News.

-ABC News’ Conor Finnegan

An advisor to Ukrainian President Volodymyr Zelenskyy said that U.S. Secretary of State Antony Blinken and U.S. Defense Chief Lloyd Austin are meeting with Ukraine's leader on Sunday in Kyiv.

The adviser, Oleksii Arestovich, said in an interview on Ukrainian TV late Sunday that the talks are going on "right now."

-ABC News' Jason Volack

At least one person -- a journalist -- was killed in a rocket attack on a residential building in Kyiv on Thursday evening, ABC News has learned.

Kyiv Mayor Vitali Kilitschko said Friday that rescuers had found the body of a victim amid the rubble.

Radio Liberty, a service of the U.S.-funded Radio Free Europe/Radio Liberty, reported that one of its employees, Vira Gyrych, was killed when a Russian missile hit her apartment in the Ukrainian capital on Thursday. Her body was found beneath the wreckage Friday morning, according to the report.

Gyrych had worked as a journalist and producer for Radio Liberty's Kyiv bureau since 2018. Prior to that, she worked for leading Ukrainian television channels, according to Radio Liberty.

"The editorial staff of Radio Liberty expresses its condolences to the family of Vira Gyrych and will remember her as a bright and kind person, a true professional," Radio Liberty said in its report.

Israeli Ambassador to Ukraine Michael Brodsky also confirmed Gyrych's death in a Twitter post, saying she was a former employee of the Israeli embassy in Kyiv.

Thursday's rocket attack came as United Nations Secretary-General Antonio Guterres visited Kyiv. Five Russian missiles flew into the city, according to Ukrainian President Volodymyr Zelenskyy. At least 10 people were injured, including four who were hospitalized, according to the Kyiv City Council.