US Republican and Democratic senators united on Monday night to stop President Donald Trump easing sanctions on Russia.

They agreed a package extending sanctions on Moscow — including on arms sales to Syrian government forces fighting Isis — and made cancelling them dependent on a congressional review, making it harder for Mr Trump to lift them.

The banking and foreign relations committees also announced a draft amendments to the Iran sanctions Bill.

It was drafted by hard-line neocon Republicans Mike Crapo and Bob Corker and Democrats Sherrod Brown and Ben Cardin.

The amendment “maintains and substantially expands sanctions against the government of Russia in response to the violation of the territorial integrity of the Ukraine and Crimea, its brazen cyber­attacks and interference in elections, and its continuing aggression in Syria,” said Republicans and Democrats on the committees.

Penalties would also be slapped on those responsible for malicious cyber activity allegedly on behalf of the Russian government.

The committees are set to vote on the amendment today, but bipartisan support was expected.

The existing sanctions were imposed after Crimea voted to secede from Ukraine following the 2014 far-right coup and reunite with Russia.

Senate Democrat minority leader Chuck Schumer said: “We are ensuring that the United States continues to punish President [Vladimir] Putin for his reckless and destabilising actions.”

Earlier on Monday, Defence Secretary James Mattis told the House armed services committee that he had seen nothing to indicate that Mr Putin was interested in co-operation with the US.

“Mr Putin has chosen to be a strategic competitor,” he said.