Boris Johnson says there is "abundant evidence" of Russian interference in elections in the US and German elections.
The foreign secretary made the comment following talks with Russian counterpart Sergei Lavrov in Moscow.
Johnson also admitted "things are not easy" between Britain and Russia, while Lavrov had said before the talks that "our relations are at a low point" and blamed Johnson and other Western politicians.
Russia's alleged interference in the US election is the subject of a probe led by special counsel Robert Mueller, and separate investigations by both houses of Congress. The Mueller probe has led to the dismissal of Trump's former national security advisor Michael Flynn, who now faces charges of lying to the FBI.
Republican poliicians have claimed the Mueller inquiry is biased against Trump, citing texts from an FBI agent involved in the probe, and there have even been suggestions that the President could fire Mueller - although Trump himself has rejected this idea.
Johnson's visit to Russia has been decidedly frosty, with the Foreign Secretary warning Russia that Britain is ready to retaliate to cyber attacks - a comment which earned him a rebuke from counterpart Sergey Lavrov as the two met in Moscow.
The Foreign Secretary told Lavrov that, although London and Moscow were at loggerheads over Ukraine, the Balkans and alleged online meddling by the Russians, both sides had a duty to work together on global priorities like preserving the Iranian nuclear deal and countering the threat to stability from North Korea.
He also welcomed signs of increasing trade, joking that 300 Bentley cars were sold in Russia last year, "not, I believe, necessarily to employees of the Foreign Ministry."
However Johnson also sent a blunt message to the Kremlin to stop its use of cyberspace to disrupt Western countries.
He told reporters: "The UK is certainly prepared and able to respond, should we so desire."
Lavrov responding to Johnson by saying that "we would prefer to talk about our mutual concerns not before a mike and at a tribune, but directly."