WASHINGTON( Reuters) – U.S. senators reached an agreement on Monday on legislation enforcing new sanctions on Russia, including a provision that would prevent the White House from easing, suspending or aiming sanctions without congressional approval.

The agreement, to be filed as an amendment to an Iran sanctions bill, is intended to punish Russia over issues including its alleged meddling in the 2016 U.S. election, annexation of Ukraine's Crimea region and is supportive of the government of Syria in that country's six-year-long civil war.

The Iran bill is due come up for a referendum as soon as this week.

Besides the provision setting up a process for Congress to review changes in sanctions, the measure would put into statute sanctions previously established via presidential executive order, including some on certain Russian energy projects and indebtednes financing in some industries.

It would impose new sanctions on Russians found to be guilty of human rights abuses, supplying weapons to Syria's government and conduct cyber attacks on behalf of Russia's government , among others.

The measure also would allow new sanctions on Russian mining, metals, shipping and railways.

The legislation is backed by both Republican and Democrats, and is expected to easily pass the Senate.

It was introduced amid an intense focus in the U.S. capital on the relationship with Russia, and investigations by the Department of Justice and congressional committees of whether Russia sought to influence the 2016 U.S. elections to help elect Republican President Donald Trump, and whether Trump associates colluded with Moscow as it sought to influence the election.

Aaron Bernstein/ Reuters Senate Minority Leader Chuck Schumer said the new sanctions will send a warning to any country even thinking about hacking future elections.

To become law, the legislation would have to pass the House of Representatives and be signed into statute by Trump. If Trump objected, some of its backers said they expected enough congressional support to override a veto.

” These additional sanctions will … send a powerful and bipartisan statement to Russia and any other country who might try to interfere in our elections that they will be punished ,” Senate Democratic Leader Chuck Schumer said in a statement.

Russia has denied attempting to interfere in the U.S election, and Trump has rejected any talk of collusion.

The measure also approves” robust assistance” to strengthen democratic institutions and counter disinformation in European countries that might be targeted by what the legislation's sponsors described as Russian aggression.

In December, the final full month of President Barack Obama's administration, Washington sanctioned Russian businessmen and companies for Moscow's role in Ukraine via executive order.