Mitch McConnell, the top Republican in the U.S. Senate, paid an unannounced visit to Kyiv on Saturday with other Republican senators and met Ukrainian President Volodymyr Zelensky for talks.
McConnell is pressing Republican Senator Rand Paul to end his opposition to a $40 billion aid package for Ukraine, which has overwhelming support from both major parties.
Zelensky hailed what he said was a powerful signal of bipartisan support for Ukraine.
"Thank you for your leadership in helping us fight not only for our country, but also for democratic values and freedoms. We really appreciate it," he said in a statement.
McConnell was accompanied by Susan Collins of Maine, John Barrasso of Wyoming and John Cornyn of Texas.
Dozens of foreign politicians and celebrities have visited Ukraine since the Russian invasion in February to show their support. President Joe Biden's wife, college professor Jill Biden, made an unannounced trip to Kyiv last Sunday.