Former British Prime Minister Boris Johnson met with Republican leadership and key players on Capitol Hill on Tuesday, lobbying to maintain support of Ukraine in its fight against Russia.

Johnson met with Senate Minority Leader Mitch McConnell (R-Ky.) and Rep. Jim Banks (R-Ind.), and is slated to speak to the Republican Study Committee on Wednesday. Johnson is making the rounds to Republican lawmakers as GOP support for the level of U.S. funding of Ukraine has started to falter.

As Republicans have taken on their new majority in the House, conservative members have voiced concerns about the ongoing flow of U.S. aid to Kyiv. Speaker Kevin McCarthy (R-Calif.) said in October, before he assumed the gavel, that the party would not offer a “blank check” for the U.S. funding of Ukraine. 

Johnson was a strong supporter of Ukraine while he was prime minister and strengthened the ties between the warring state and Britain. He stepped down as prime minister in September following a string of scandals.

He visited Ukraine last week, meeting with the country’s President Volodymyr Zelensky. 

His visit to Capitol Hill also comes as western allies have ratcheted up their military support of Ukraine, with the U.S. and Germany both agreeing to send tanks to the country last week.

—Alexander Bolton and Emily Brooks contributed.