WATCH: White House press secretary says Biden reaffirmed U.S. commitment to Ukraine in call with Zelenskyy

President Joe Biden reaffirmed the U.S. commitment to Ukraine Thursday during a call with Ukrainian President Volodymyr Zelenskyy, a day after the six-month mark of the war with Russia.

Watch the full event in the player above.

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Speaking to reporters at the White House briefing, press secretary Karine Jean-Pierre said Biden “reiterated the United States’ support for Ukraine as they defend themselves from Russian aggression,” and “congratulated Ukraine as it marked a particularly significant Independence Day this week.”

Jean-Pierre added that Biden and Zelenskyy discussed U.S. security assistance, including an additional nearly $3 billion tranche of aid that the U.S. administration announced Wednesday.

The two leaders also reiterated their call for Russia to return full control of the Zaporizhzhia to Ukraine and for the International Atomic Energy Agency to be given access to the plant.

Russian President Vladimir Putin ordered a major buildup of his country’s military forces Thursday in an apparent effort to replenish troops that have suffered heavy losses in six months of bloody warfare and prepare for a long, grinding fight ahead in Ukraine.

Regarding the ongoing negotiations over restarting the Iran nuclear deal, Jean-Pierre offered few details about the White House response to Iran’s latest offer to resume its compliance, saying only the administration is “not going to negotiate in public,” but the channels of communication remain open.

The Biden administration responded Wednesday to Iran’s latest offer, but neither side is providing a definitive path to revive the agreement, which has been on life-support since former President Donald Trump withdrew from it in 2018.

“If Iran is prepared to comply with its commitments under the 2015 deal, then we’re prepared to do the same. The administration, along with our allies, is preparing equally for scenarios with and without a mutual return to full implementation of the JCPOA,” she said.

Asked about the administration’s response to Nicaraguan President Daniel Ortega’s administration detaining several Roman Catholic clergy, including a bishop, who have been critical of Ortega, Jean-Pierre called it “unacceptable” and said the White House “condemns the actions.”

“There has been a dramatic deterioration of respect for democratic principles and human rights by the regime in Nicaragua, including the imprisonment of Democratic leaders, members of the political opposition, students and journalists,” she said.

“The United States and members of the international community have already taken a number of actions to promote accountability for the regime’s actions and will continue to do so,” the press secretary added.