(NB. These blades could be accessed by other groups or individuals for attack purposes)

London transport staff have been warned after anti-mask posters with razor blades on the back were found, a union has said.

The Rail, Maritime and Transport (RMT) union said it had raised the issue of "Masks Don't Work" posters with Transport for London (TfL).

TfL said it was not aware of any incidents involving blades but had given advice to its workers.

A similar poster was found in Cardiff where a woman was injured removing it.

The RMT called for the courts to take the "hardest possible line" against those found responsible.

Beijing has been accused of sponsoring an attack on Microsoft Exchange email servers earlier this year which "recklessly" exposed thousands of businesses to criminal hackers.

The Chinese government has been accused of "systematic cyber sabotage" in statements by the UK and allies, including the US and Canada.

The allies are announcing that they believe Chinese state-sponsored hackers were responsible for an attack earlier this year which "indiscriminately" compromised an estimated 400,000 servers worldwide, leaving them exposed to criminals.

More than 70 organisations in the UK were compromised by the hack, perpetrated by a group associated with Beijing according to the National Cyber Security Centre. This attribution has been supported by allies.

Foreign Secretary Dominic Raab described the hacking campaign - which is believed to have compromised the on-premise email servers indiscriminately with an intention to subsequently target specific victims - as "a reckless but familiar pattern of behaviour" from the Chinese government.

Four Iranian intelligence officials have been charged with plotting to kidnap a New York-based journalist critical of Iran, US prosecutors say. The indictment did not name the target, but Masih Alinejad, an Iranian-American author and activist, says it was her.

The conspirators, who all live in Iran and remain at large, also allegedly plotted to lure a person in the UK and three others in Canada to Iran. All of the targets had been critical of Iran, according to the indictment.

The US justice department says the Iranian officials sought to lure the New York-based journalist to a third country where the abduction was planned. The plotters even offered money to the writer's relatives in Iran to betray them, which they refused to do, the indictment contends.

They hired private investigators to spy on the target's Brooklyn home and family, and set up a live video feed of the property. They also researched a service offering military-style speedboats for evacuation from New York City, and maritime routes to Venezuela, an ally of Iran.

There was no immediate response from the Iranian government.