A U.S. senator sponsoring a bill for wide-ranging sanctions on Russia said on Wednesday he was hopeful it would pass the House of Representatives next month, and be a “sledgehammer” to President Vladimir Putin’s efforts to fund his war in Ukraine.

Senator Richard Blumenthal, a Democrat from Connecticut who met with Ukrainian President Volodymyr Zelenskiy and senior officials during a visit to Kyiv, said the bill had strong Republican support in the House, after comfortably passing an initial Senate vote last month.

“Putin understands only force,” Blumenthal told a news conference. “And the Russia sanctions bill is a sledgehammer that can have the kind of force Putin understands.”

Though Democrats are broadly supportive of the sanctions, some have expressed concern that it would give Republican President Donald Trump leeway to impose additional tariffs, including on U.S. allies.

The bill would sanction top Russian officials and allow Trump to set tariffs of up to 100% on the top buyers of Russia’s oil and gas, which include China and India, in an effort to stem revenue flows to Moscow.

Blumenthal said exemptions in the bill would spare European allies from the imposition of tariffs, allaying concerns raised by some Democratic legislators.

Blumenthal said he had asked Zelenskiy to lobby members of the House of Representatives to support its passage.

Zelenskiy spoke to several senators in Washington last month ahead of the vote on the bill, which took place on the day of the funeral of its co-author, the late Senator Lindsey Graham.

Blumenthal said Zelenskiy had “heartily and readily agreed” to his request. Ukraine’s presidency did not immediately respond to a request for comment.

(Reporting by Daniel FlynnEditing by Bill Berkrot)