Former U.S. Vice President Mike Pence, who is running for the Republican nomination in the 2024 presidential election, made a surprise visit to Ukraine on Thursday to meet with the country's president Volodymyr Zelenskiy, Pence announced via Twitter.

Visiting Ukraine "just steels my resolve to do my part, to continue to call for strong American support for our Ukrainian friends and allies," Pence told NBC News in an interview from Kyiv.

He is the first Republican presidential candidate to meet with Zelenskiy during the campaign.

Pence has been a vocal critic of Russian President Vladimir Putin and full-throated supporter of Ukraine, as he takes on his former boss, ex-President Donald Trump, for the Republican nomination.

Zelensky says ‘world must react’ to Kakhovka dam attack

Trump has declined to say he wants Ukraine to win the war, instead saying he wants a negotiated solution between Russia and Ukraine.

Pence currently trails Trump by over 30 points in most polls among Republican primary voters who will chose next year's candidate to take on Democratic President Joe Biden.

Pence also made visits to three cities and villages near Kyiv - Bucha, Irpin and Moschun - to view the destruction from Russian shelling since the invasion in February last year, according to CNN.

The issue of Ukraine has divided Republican presidential candidates in the fight for the White House nomination. Trump's closest rival for the nomination, Florida Governor Ron DeSantis, has questioned the amount of aid that should be provided for Ukraine, while Nikki Haley, Trump's former U.N. ambassador, and U.S. South Carolina Senator Tim Scott, back continuing support.