The US Senate on Thursday overwhelmingly passed tough sanctions on Russia and Iran, sending the House of Representatives a bill that would prevent President Donald Trump from unilaterally easing penalties against Moscow.

The measure, which passed on a 98-2 vote, seeks to make Tehran pay a price for its "continued support of terrorism."

It also aims to punish Russia's Vladimir Putin for interfering in last year's US election, and to make it tougher for the White House to roll back sanctions.

US intelligence chiefs have concluded that Russia orchestrated a campaign to undermine the American election process that included espionage and cyber-attacks, as a means to tilt the vote in Trump's favor.

"Not only did we pass a new round of tough sanctions for Russia's meddling in our election, we codified existing sanctions into law, making them harder to lift, and we moved to make Congress -- not the president -- the final arbiter of sanctions relief when necessary," top Senate Democrat Chuck Schumer said before the vote.

"Any idea of the president's that he can lift sanctions on his own for whatever reason are dashed by this legislation."

The bill as originally introduced was exclusively about slapping new sanctions on Iran. But lawmakers attached a bipartisan amendment on Russia to it early this week.

The addition came with the White House deeply embroiled in crisis over whether Trump's campaign team colluded with a Russian effort to sway the 2016 election.

The measure would require a green light from Congress in the event sanctions on Russia are relaxed, suspended or terminated.

It would codify in law the sanctions imposed by executive decree by Trump's predecessor Barack Obama, especially against the Russian energy industry.

- 'Strong' legislation -

And it would impose new sanctions on "corrupt Russian actors," those implicated in serious human rights abuses or who supply weapons to Bashar al-Assad's regime in Syria, and people who conduct "malicious cyber activity" on behalf of the Russian state.

"This is a very, very strong piece of legislation," Senate Foreign Relations Committee chairman Bob Corker said on the Senate floor.

Corker, too, sounded pleased that the bill effectively ties a president's hands when it comes to unwinding certain sanctions on Russia.

"Today the United States Senate is asserting its responsibilities" regarding foreign policy, he added.

The sanctions follow the scandalous departure of Michael Flynn as Trump's national security advisor.

Flynn had been misleading about his phone conversations late last December that reportedly included talks with Russian ambassador Sergey Kislyak, just as then-president Barack Obama was ordering new sanctions on Russia over its alleged election meddling.

The new Iran restrictions, which impose mandatory sanctions on people involved with the Islamic republic's ballistic missile program and those that transact with them.

It also applies terrorism-related sanctions to the Islamic Revolutionary Guard Corps, and re-enforces aspects of the arms embargo on Iran.

Senate Republican Lindsey Graham said the sanctions send a strong signal that "business as usual with Iran is over."

The bill now heads to the House, where its fate is less certain.

The White House has yet to announce its position on the legislation, and whether it approves of a process of congressional review that would essentially restrict the president's actions with regard to Putin's government.