LONDON (AP) — A U.K. newspaper has published more leaked memos revealing a British ambassador's blunt assessments of the Trump administration, including one in which the envoy to Washington claimed President Donald Trump pulled out of the Iran nuclear deal to spite predecessor Barack Obama.

In the May 2018 cable published by the Mail on Sunday, U.K. Ambassador Kim Darroch called Trump's decision to abandon the international accord "an act of diplomatic vandalism, seemingly for ideological and personality reasons" because the pact "was Obama's deal."

Darroch wrote the memo after then-Foreign Secretary Boris Johnson visited Washington in a failed attempt to persuade the United States not to abandon the 2015 nuclear agreement.

He alleged the White House had no strategy for what would come after its withdrawal and "no sort of plan for reaching out to partners and allies."

The newspaper published new details from confidential diplomatic cables despite a police warning that making the documents public might be a crime.

Scotland Yard is hunting for the perpetrator who leaked confidential diplomatic cables to the Mail on Sunday. Last week the newspaper published memos from Darroch describing the Trump administration as dysfunctional and inept.

The publication of the ambassador's unguarded views, meant for a small group of ministers and senior officials in London, cost him his job.

Trump responded by calling Darroch "very stupid" and a "pompous fool" in a Twitter fusillade, and the White House cut off contact with the British envoy.

Darroch announced his resignation Wednesday, saying "the current situation is making it impossible for me to carry out my role as I would like."

He remains formally in the post while a successor is chosen for one of Britain's most important diplomatic jobs.

British politicians and officials are embarrassed at the leak of Darroch's frank — though widely shared — opinions about Trump. And they are angry that a British ambassador was forced to step down because of pressure from a foreign leader.

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Some also blame Johnson, who is likely to become Britain's next prime minister, for refusing to publicly defend Darroch after Trump posted disparaging tweets about the ambassador for two days. Darroch has said Johnson's silence contributed to his decision to quit.

British officials have said they have no evidence that hacking was involved in the documents' release, and that the culprit is likely to be found among politicians or civil servants in London.

Rumors are swirling in government circles in London about who was behind the leak, widely seen as benefiting supporters of Brexit and Trump.

The journalist who reported the cables, Isabel Oakeshott, is a strong supporter of Brexit and an ally of Brexit Party leader Nigel Farage, who also is Britain's leading champion of Trump.

Farage has accused Darroch of lacking enthusiasm for Britain's departure from the EU and said he should be replaced with "a non-Remainer who wants a trade deal with America."

Police are investigating the leak as a potential breach of the Official Secrets Act, which bars public servants from making "damaging" disclosures of classified material. Breaking the act carries a maximum sentence of two years in prison, though prosecutions are rare.

Contentiously, police issued a warning to journalists that publishing the documents "could also constitute a criminal offence."

Both Johnson and Jeremy Hunt, his rival in the race to be Britain's next leader, defended the media's right to publish. And the Mail on Sunday said publication was in the public interest.

"Our readers across the globe now have important information about how Britain tried, but failed, to stop President Trump abandoning the Iran nuclear deal," the newspaper said in a statement.

"What could be more in the public interest than a better understanding of how this position was reached, which may have serious consequences for world peace?"