Donald Trump has blocked numerous sanctions on Russia two days before they were due to take effect, as a row with his Ukrainian counterpart Volodymyr Zelensky deepens.

The sanctions were passed by the US Congress and signed into law by the US president in September.

But Trump issued an executive order on Friday night saying that suspending some was in the US national interest, prompting a backlash from US lawmakers. Zelensky said it was unfortunate the US has decided to "completely disregard" the sanctions.

Russian envoy Kirill Dmitriev said Trump's order was "an important and truly historic moment", and that the sanctions would have inflicted "serious damage" on the US and global market.

Relations between Washington and Kyiv frayed after the US struck a controversial deal to import Russian diesel last week. Ukraine has accused the Trump administration of withdrawing key military support.

Since then, Ukraine's president declared it was nice to be among "real leaders" while addressing an EU summit, after Trump said Zelensky was "more difficult to deal with" than Russian President Vladimir Putin.

The sanctions suspension seemed to add further fuel to the fire.

Zelensky said on Saturday morning that the sanctions "could have helped enormously" and that the law was "supposed to impose truly effective pressure on Russia to bring this war to an end".

He pointed to Russian overnight attacks on 15 Ukrainian energy facilities that had caused power cuts in several regions and said: "Russia is trying to cause a blackout in Ukraine – right before winter."

Zelensky said it was "important that everyone in America also sees what is really happening" on the ground.

The new US sanctions law took aim at Russia's economy by giving Trump broad powers to levy tariffs of up to 100% on imports from the top five purchasers of Russian oil and gas – most significantly China and India.

It also included sanctions against senior Russian figures, including Putin, as well as Russian financial institutions and Moscow's so-called "shadow fleet" of vessels used to circumvent existing embargoes.

US Secretary of State Marco Rubio said that the suspension would consist of a 60-day pause to allow for the Trump administration to analyse the impact they might have on the US and global economy.

Trump denies limiting Ukraine access to Starlink network

Trump 'completely wrong' to restrict support for Ukraine, Italian minister tells BBC

The suspension drew criticism from US politicians from both main parties.

Democrats including the Virginia Congressman Don Beyer criticised the move, accusing Trump of capitulating to Moscow and turning his back on Kyiv and Zelensky.

A handful of Republicans also came out against the move.

Texas Senator Ted Cruz, a Trump ally, called waiving the sanctions a mistake, telling Fox News that there were other ways to address fuel prices, while the state's other Senatory John Cornyn called the move "reckless".

North Carolina Senator Thom Tillis called it "beyond irresponsible", arguing that Trump could bring energy prices down by ending the Iran war instead of "doing a solid" for Putin.

Nebraska Representative Don Bacon indicated that US lawmakers will now resist funding Trump's agenda.

Watch: Will Ukraine get the support needed as tensions with US rise?

Zelensky has long stressed the need for stringent sanctions to limit funding that Russia can use in its war effort.

He told reporters on Saturday that he believed the Trump administration would lift more sanctions against Russia.

Zelensky and Ukraine's European allies initially criticised Trump for his plans to import Russian diesel in the hope of bringing down US energy prices, which have skyrocketed during the Iran war.

Trump has spent months grappling with the political consequences of rising fuel costs ahead of the US midterm elections, with inflation souring his standing with the American public.

Zelensky suggested the deal was tantamount to the US investing in Russia's war effort.

A few days later, Trump claimed that both Russia and Ukraine had agreed to an "energy ceasefire" to facilitate the export of Russian diesel. Both nations have been intensively striking one another's energy infrastructure.

Zelensky expressed surprise at the announcement, and said Kyiv would stop the strikes if Russia did the same. After three days of fresh attacks from Russia, Kyiv resumed its strikes on Russian oil refineries.

Trump condemned the Ukrainian strikes as a disgrace, but Zelensky said he was "only standing up for Ukraine's interests".

Zaporizhzhia was among regions hit by Russian strikes overnight

Concerns that Trump is siding with Russia have been heightened by disruption to a US-provided satellite system used by Ukraine.

Last week, Starlink suddenly and unexpectedly restricted the speed at which drones could fly while still maintaining internet connection. This disrupted some battlefield missions, Ukraine said, and hampered Kyiv's ability to protect itself from incoming Russian attacks.

Zelensky told reporters on Saturday that Ukraine had been told by US officials the speed restrictions were linked to technical issues.

However, he said Ukraine had tested Starlink on EU territory and found "these problems do not exist" and the system was operating at higher speeds.

Trump has denied deliberately slowing down the network and denied another accusation by Zelensky that US had withdrawn intelligence-sharing.

Ukrainian authorities said that at least nine people have been killed and around 60 injured in Russian strikes across the country since Friday. That included an ambulance driver killed and 20 others injured in a Russian strike on the city of Kherson, they said.

Additional reporting by Helen Sullivan and Sareen Habeshian

Zelensky says Ukraine has right to defend itself after Trump calls latest strikes a 'disgrace'

Trump faces growing backlash over plans to import diesel from Russia

Russia accuses Ukraine of attacking oil refinery after Zelensky says strikes to resume