Police in Vienna have put more armed officers on the streets after intelligence suggested a possible Islamist terror attack was being planned against churches.

“There is a nonspecific threat of an assault against churches,” police in the Austrian capital tweeted.

“If there is a concrete danger for the population at a concrete location, Vienna police will warn immediately via all available channels,” the force added.

They said the country’s intelligence service had received information suggesting “an assault with an Islamistic motive is planned to be carried out”.

Officers with “special equipment” are conducting increased patrols at “points of interest” in the city, tweeted Polizei Wien.

It is currently unclear how long the alert will last.

Armed police in bulletproof vests and helmets will be more visible and will also be checking traffic, a police spokesman told Radio Wien.

A spokesman for the archdiocese of Vienna said churches would stay open “for the time being” because police had informed them it was a “general threat” with “no imminent danger for Catholics”.

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People have been asked not to share video or images of the operation as it could endanger officers and help “potential perpetrators”.

Vienna is among the safest capital cities in Europe but in November 2020 an Islamic State sympathiser shot dead four people before being killed by police.

The attacker wore a fake suicide belt and opened fire in the city centre as people were enjoying final meals before a coronavirus lockdown began.