HELSINKI — Donald Trump on Monday blamed bad relations between Moscow and Washington on the US investigation into alleged Russian election meddling — and Russia promptly agreed.

Setting the scene just hours ahead of his summit with Vladimir Putin, Trump took to Twitter to lash out at US special prosecutor Robert Mueller’s probe.

“Our relationship with Russia has NEVER been worse thanks to many years of US foolishness and stupidity and now, the Rigged Witch Hunt!” Trump tweeted, with a swipe at his White House predecessors.

Many Twitter users expressed anger or surprise that a US leader had blamed his own country for the rift, despite Russia’s interventions in Syria and Ukraine and alleged subversion of Western elections.

But the Russian foreign ministry was delighted, jumping in through its official Twitter account to first “like” Trump’s message then to re-tweet it with a clear response: “We agree.”

Last week, Mueller indicted 12 Russian intelligence officers accused of hacking computer servers used by Trump’s 2016 election rival Hillary Clinton, then leaking private emails to damage her campaign.

Trump has furiously denied his own campaign colluded in the alleged interference, and has generally denounced the special investigation as a “witch hunt” promoted by his enemies to delegitimize his victory.

At the same time, the US leader has promised to bring up the issue on Monday at his summit with Putin in Helsinki — but has been vague on whether he will call on Moscow to extradite the indicted suspects.

Democrats had called for the summit’s cancellation after new revelations surrounding the alleged election meddling.

But Trump has insisted it is “a good thing to meet”, as he attempts to replicate with Putin the sort of personal rapport he proclaims with the autocratic leaders of China and North Korea.

If the pair do find common ground, then the summit may take the heat out of some of the world’s most dangerous conflicts, including Syria.

But there are many points of friction that could yet spoil Trump’s hoped-for friendship with the wily former KGB spymaster.

After a stormy NATO summit in Brussels last week, Trump was accused by critics of cozying up to Putin while undermining the transatlantic alliance.

But over breakfast with Niinisto, he insisted NATO “has never been stronger” and “never been more together” thanks to his insistence on all allies paying their fair share.

With Washington and Moscow at loggerheads over Ukraine, Iran and trade tariffs as well as Syria, even Trump has cautioned that he is not approaching the Putin summit “with high expectations”.

The brash 72-year-old billionaire has been president for 18 months while Putin, 65, has run Russia for the past 18 years.

In a weekend interview with CBS News, Trump admitted that Russia remains a foe, but he put Moscow on a par with China and the European Union as economic and diplomatic rivals.

The Kremlin has also played down hopes that the odd couple will emerge from their first formal one-on-one summit with a breakthrough.

Putin, who arrived in Helsinki on Monday after playing host at the World Cup final in Moscow on Sunday, has remained terse in the run-up to the summit.

On Friday his adviser Yuri Ushakov played down expectations, saying: “The state of bilateral relations is very bad.... We have to start to set them right.”

Indeed, after the bad-tempered NATO summit and a contentious trip by Trump to Britain, anxious European leaders may be relieved if not much comes out of the Helsinki meeting.

Those leaders are already fuming over Trump’s imposition of trade tariffs on various countries, including Russia. — Agencies