WASHINGTON, June 29 (Reuters) - Former US Vice President Mike Pence, who is running for the Republican nomination in the 2024 presidential election, made a surprise visit to Ukraine on Thursday (Jun 29) to meet President Volodymyr Zelenskyy.

"Freedom is winning in Ukraine, and now more than ever, we need to keep faith with the courageous fighters here in Ukraine who are standing for freedom and pushing back on Russian aggression," Pence told reporters after meeting with Zelenskyy.

Pence is the first Republican presidential candidate to meet Zelenskyy 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.

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

Pence 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 see 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 UN ambassador, and US South Carolina Senator Tim Scott, back continuing support.

"I have confidence a day will come when Ukraine's sovereignty will be restored," Pence told reporters, adding that the "free world will not stand" for Russia's invasion.