BuzzFeed’s decision to publish an intelligence report filled with salacious and unsubstantiated claims about Donald Trump’s purported behaviour in Russia has triggered a political storm and debate over media ethics.

The news website posted the unredacted documents on Tuesday, just 10 days before Trump’s inauguration, with a warning that the contents contained errors and were “unverified and potentially unverifiable”.

The decision to put the claims in the public domain forced other media outlets to repeat the allegations or ignore a story that lit up the internet. Some critics rounded on BuzzFeed, calling it irresponsible.

The documents, reportedly compiled by a British former intelligence agent, alleged that the Kremlin was “cultivating, supporting and assisting” Trump for at least five years.

They also alleged that Russian spies had exploited the president-elect’s “personal obsessions and sexual perversion” to gather compromising material.

The president-elect denied and denounced the claims in a series of tweets.

The memos were compiled by the former intelligence officer on behalf of some of Trump’s Republican opponents in the primaries, and later for Democrats.

Other media outlets including the Guardian had obtained and reviewed the documents in recent weeks but declined to publish because there was no way to independently verify them.

The stakes rose on Tuesday when CNN reported that America’s intelligence chiefs had given Trump and Barack Obama a two-page summary of the reports last week. CNN and the Guardian also reported that Senator John McCain had delivered a copy to the FBI director, James Comey, last month, but withheld the documents’ most eye-opening details, citing lack of corroboration.

An hour after CNN’s initial story, BuzzFeed went ahead and published the documents. “Now BuzzFeed News is publishing the full document so that Americans can make up their own minds about allegations about the president-elect that have circulated at the highest levels of the US government,” the site said in an accompanying note.

The news site noted the documents’ provenance and the fact that they contained “some clear errors”, such as misspelling the name of a Russian company.

Ben Smith, the editor-in-chief, followed up a few hours later with a statement that defended publication as an act of journalistic transparency in a hyper-partisan era.

“Publishing this document was not an easy or simple call, and people of good will may disagree with our choice. But publishing this dossier reflects how we see the job of reporters in 2017.” Smith amplified the warning in BuzzFeed’s original story by saying there was “serious reason to doubt the allegations”.

Some prominent journalists and media executives excoriated BuzzFeed.

“Even Donald Trump deserves journalistic fairness,” tweeted David Corn, Mother Jones’s Washington bureau chief who reported in October on the existence – but not the contents – of memos from a “former western intelligence officer”.

“Rare that a story stinks from every possible angle: the source, the content, the consequence, the messenger, the target,” tweeted Wolfgang Blau, chief digital officer of Condé Nast International and a former Guardian executive.

“Not how journalism works: Here’s a thing that might or might not be true, without supporting evidence; decide for yourself if it’s legit,” tweeted Brad Heath, an investigative reporter for USA Today.

Adam Goldman of the New York Times blamed CNN for opening the can of worms. “Sequence of events: @CNN finds way to talk about report and @buzzfeed uses that as reason to publish. Media critics are gonna be busy,” he tweeted.

On the other hand, Richard Tofel, the president of the investigative news organization ProPublica, applauded Buzzfeed, saying “citizens should have evidence to consider for themselves”.

And the blog Lawfare said the allegations, though unproven, needed to be taken seriously because intelligence chiefs appeared to be giving them some credibility. Trump, it noted, had consistently rejected intelligence reports that Russia had hacked the US election.

“All of which is to say to everyone: slow down, and take a deep breath. We shouldn’t assume either that this is simply a ‘fake news’ episode directed at discrediting Trump or that the dam has now broken and the truth is coming out at last. We don’t know what the reality is here, and the better part of valor is not to get ahead of the facts – a matter on which, incidentally, the press deserves a lot of credit.”

In London, Jim Waterson, UK political editor of Buzzfeed, told an audience at a previously planned event about fake news: “The documents are unverified and yet this is a document which is being discussed across media circles and across security circles. If it is being briefed to the president-elect then it’s better to be able to see what he’s being briefed.”

Speaking at the same event, a panel on Fake News and the Fallout presented by the Edinburgh international TV festival and ITN, Brian Stelter, host of CNN’s Reliable Sources, said: “My gut reaction to this this morning was that if Buzzfeed hadn’t decided to publish the documents someone would have. I’m not saying whether it’s right or wrong but … this kind of raw material is always going to end up somewhere on the internet.”

BuzzFeed co-founder Jonah Peretti said in a statement: “We stand with Ben on his decision to publish this newsworthy document, which was reported on by multiple news outlets and seen by high level government officials including the president and president-elect.”

A survey of UK coverage on Wednesday morning by the UK Press Gazette found the Mirror, Mail, Sun and Express had reported some of the lurid details in the dossier – accompanied by denials from Trump and the Kremlin – while the Independent and Guardian had reported some of the detail and the denials. The Daily Telegraph had a story based on denials with none of the detail, and the Times had not yet covered the story online.

Roy Greenslade, who teaches journalistic ethics at City University’s school of journalism and writes a column for the Guardian, said the publication of the documents was an error.

“I’m all for disclosure, but news outlets must act responsibly and should also beware of doing anything that undermines their credibility,” he said. “On both counts, Buzzfeed’s decision to publish the material was an error. It is disingenuous to publish the document on the grounds that ‘Americans can make up their own minds’. Adopting that criterion would allow for the publication of anything irrespective of its authenticity.”

The New York Times, which goes by the slogan “all the news that’s fit to print”, said it was “not in the business of publishing things we can’t stand by”. Dean Baquet, the executive editor, described the allegations as totally unsubstantiated.

“We, like others, investigated the allegations and haven’t corroborated them,” he said, explaining why the newspaper did not publish.