U.S. Vice President Mike Pence waits before a meeting with Ukraine's President Volodymyr Zelenskiy, in Warsaw, Poland, Sunday, Sept. 1, 2019. (AP Photo/Petr David Josek)

WARSAW, Poland (AP) — Vice President Mike Pence has assured Ukraine's president his country has U.S. support after President Donald Trump advocated for letting Russia re-join the Group of Seven despite its annexation of Ukraine's Crimea Peninsula.

Pence met with Ukrainian President Volodymyr Zelenskiy after observances marking the start of World War II 80 years ago in Poland. They talked in the wake of Trump's comments and his administration's decision to hold up $250 million in security aid to Ukraine.

Pence said the United States had "stood strongly for the territorial integrity of Ukraine" when Russia seized Crimea in 2014. Ukraine and most other nations see the move as illegal.

He added: "We will continue to stand with the people of the Ukraine on your security, on territorial integrity, including the Ukraine's rightful claim to Crimea."

Ukraine's President Volodymyr Zelenskiy, left, sits next to U.S. Vice President Mike Pence, during a bilateral meeting in Warsaw, Poland, Sunday, Sept. 1, 2019. (AP Photo/Petr David Josek)
Ukraine's President Volodymyr Zelenskiy, left, shakes hands with U.S. Vice President Mike Pence, in Warsaw, Poland, Sunday, Sept. 1, 2019. (AP Photo/Petr David Josek)
U.S. Vice President Mike Pence speaks during a memorial ceremony marking the 80th anniversary of the start of World War II in Warsaw, Poland, Sunday, Sept. 1, 2019. (AP Photo/Petr David Josek)