WASHINGTON (Reuters) - The top Republican and Democrat on the U.S. Senate Banking Committee both said on Wednesday that sanctions imposed on Russia over its involvement in Ukraine must not be lifted without drastic changes by Russia.

Chairman of the Senate Banking, Housing, and Urban Affairs Committee Mike Crapo (R-ID) hearing listens to testimony from Federal Reserve Chairman Janet Yellen on the “Semiannual Monetary Policy Report to the Congress” on Capitol Hill in Washington, U.S., February 14, 2017. REUTERS/Joshua Roberts

Senator Mike Crapo, the panel’s Republican chairman, said reducing sanctions could encourage Moscow to continue aggressive actions, three years after it annexed Ukraine’s Crimea region.

Senator Sherrod Brown, the ranking Democrat, said the panel should look at increasing sanctions.

“Russia remains a hostile, recalcitrant power, deploying its military, cyber-enabled information espionage activities and economic tactics to harm the United States and drive a wedge between it and its allies,” Crapo said.

President Donald Trump’s fellow Republicans and Democrats in congress have both expressed concern that Trump might reduce sanctions on Russia imposed under his predecessor, Democratic former President Barack Obama, because of Trump’s expressed desire to improve relations with Moscow.

Trump has said he intends, at least for now, to maintain U.S. sanctions.

Trump’s first national security adviser, Michael Flynn, was forced from that position last month after revelations that he had discussed U.S. sanctions on Russia with Moscow’s ambassador to the United States before Trump took office.

Brown noted a report by U.S. intelligence agencies concluding that Russia sought to interfere in the 2016 U.S. election on Trump’s behalf. He said the committee should focus on how it can strengthen its response to Russia.

Russia denies any attempt to influence the U.S. election result.

“We should strengthen, not weaken, Russian sanctions, and the president must work with Congress on a Russia policy that is clear-eyed about our adversaries and their behavior,” Brown said in his opening statement at the hearing.

Brown also said a surge in violence in Ukraine since Trump was elected president in November is a test by Moscow of the U.S. resolve to support the Kiev government and the Ukrainian people.