Police armed with assault rifles have been deployed outside churches in the Austrian capital, Vienna, following warnings of a possible "Islamist-motivated attack".

Security has been stepped-up in front of certain buildings, including churches, after undisclosed information was received by the country's intelligence service.

"There is a nonspecific threat of an assault against churches," Vienna police tweeted.

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

In their tweet, Polizei Wien gave notice that regular and special operations police officers with "special equipment" would be conducting increased patrols at "points on interest" in the city.

The street presence of officers in the Austrian capital has also been increased.

“Police officers are equipped with bulletproof helmets and vests and assault rifles. They will carry out surveillance activities and also carry out checks in road traffic,” police spokesman Markus Dittrich told local radio station Radio Wien.

In November 2020 four people were killed and 23 others wounded following an Islamist attack when a heavily armed man opened fire on people in Vienna's popular nightlife area.

The gunman was shot dead by police.

He was later identified as a 20-year-old "Islamist terrorist" who had been released early from jail, despite convictions for association with terrorism. Responsibility for his deadly attack was claimed by the jihadist group, so-called Islamic State (IS).