US Congress will be guilty of "close to criminal neglect" if it fails to pass funding for Ukraine, US President Joe Biden has said while thanking German Chancellor Olaf Scholz for his leadership in securing German military aid for Kyiv.
Scholz, who was making a whirlwind stop in Washington to lend his support to Biden's efforts to obtain funding for Ukraine, met the president at the White House to discuss Russia's war with its smaller neighbour as well as the crisis in the Middle East.
Speaking to reporters on Friday, Scholz said he had been encouraged by the US Senate's move on Thursday to advance a $US95 billion ($A146 billion) bill that includes aid for Ukraine, Israel and Taiwan after Republicans blocked compromise legislation that had included reforms to immigration policy.
The White House has sounded warnings for months that a failure by lawmakers to provide aid to Kyiv would hurt its ability to fight Russia two years after Moscow's invasion of Ukraine.
"The failure of the United States Congress, if it occurs, not to support Ukraine is close to criminal neglect. It is outrageous," Biden said in the Oval Office, in front of a blazing fire, with Scholz seated next to him.
"I'm very happy that in Europe we made now decisions to get the necessary financial support to the budget," said Scholz, speaking in English.
"Also that Germany was ready to increase its support with weapon delivery." He added: "And hopefully Congress, the House, will follow you and make a decision on giving the necessary support."
Scholz met US business executives before joining Biden at the White House for talks about the two crises that are dominating world politics.
Germany had made decisive contributions lately in support of Ukraine repelling a full-scale Russian invasion, he said.
"Now, the same must happen in the rest of Europe and also the United States," he said, noting that Russian President Vladimir Putin was counting on support for Ukraine withering.
He said his meeting with US senators on both sides of the aisle reassured him that foreign policy and security experts in Congress understood the need for sustained support for Ukraine.
Scholz said Putin had recounted "a completely absurd story about the origins of this war" in his interview with conservative US talk-show host Tucker Carlson that aired on Thursday.
"There is a clear cause and that is the will of the Russian president to annex part of Ukraine," he said.
Asked about Putin's suggestion of a prisoner swap - US journalist Evan Gershkovich of the Wall Street Journal, who has been detained in Russia for nearly a year, in exchange for Vadim Krasikov, who was convicted of the 2019 murder of a Chechen dissident in Berlin - Scholz said such issues should be discussed confidentially.
The European Union approved a four-year, 50 billion-euro ($A83 billion) facility for Ukraine last week.
Ukraine relies on Western nations for military support and financial backing.