Isis has made a terrifying threat against the Vatican in the weeks before thousands of faithful are set to descend on the Holy See for Christmas celebrations. A pro-Isis propaganda channel made the threat by releasing a poster showing a car attack.

The ominous poster, reading "Christmas blood" and "so wait..." depicts a masked jihadi driving towards St Peter's Basilica in a BMW. An assault rifle, backpack and explosives ride along in the passenger seat.

The threatening poster was released by the pro-Isis Wafa Media Foundation, according to monitor Site Intelligence Group. The terror monitoring group MEMRI said the image first appeared on anonymous messaging app Telegram on Tuesday (14 November) night.

Posters like these do not typically warn of a direct threat but instead are a call to action for lone wolf attackers waiting to strike, the Daily Mail noted.

There may be a possible rise in Isis attacks overseas after the collapse of its so-called caliphate in the Middle East, analysts say.

The terrorist organisations has claimed responsibility for a spate of deadly attacks in Europe in the last year, including those in London and Manchester. Isis has previously threatened Pope Francis and the Vatican.

In December 2016, an Isis terrorist killed a lorry driver and rammed his truck into a Christmas market in Berlin, killing 12. A year earlier, Rizwan Farook went on a rampage at his work Christmas party in San Bernardino, California. Farook and his wife, Tashfeen Malik, then went on the run and ended up being shot dead.

Isis has been driven out of its strongholds in Iraq and Syria. US-led forces declared victory recently after pushing Isis fighters out of Raqqa, the terror group's so-called capital.