Intelligence services in Europe are warning that the Islamic State terror group may be considering using bombs filled with toxic gasses on trains, metro systems or even aeroplanes.

The warning was initially given to European security agencies by an unnamed foreign intelligence service who passed on information that the Islamic State was looking into deploying chemical or biological weapons in the near future.

Even more concerning for authorities is that many of the chemicals mentioned in the report, like hydrogen sulphide, are relatively simple for terrorists to acquire, Die Welt reports.

Other potential chemicals named were chlorine and various acids which can be deadly in enclosed spaces like a subway car or an aeroplane. Acid attacks have grown to near-epidemic proportions in the UK according to Dr Martin Niall, a burn surgeon at Mid-Essex Hospital.

Though so far there has been no indication of links between acid attacks in the UK and radical Islamic terrorism, a report from earlier this year claimed that the country is now the world capital for such attacks.

The UK is now the world's acid attack capital… https://t.co/VIhcQ7jzWn — Breitbart London (@BreitbartLondon) June 26, 2017

Intelligence officials became particularly worried about the possibility of Islamic State jihadists using chemical weapons after authorities in Australia discovered a chemical attack plot in Sydney earlier this year. The cell who were to carry out the attack were said to have been directed by Islamic State fighters operating in the Middle East.

Australian police say they discovered evidence that the terrorists were conducting their own tests using hydrogen sulphide which is highly toxic.

Chemical weapons are not new for the Islamic State in the Middle East as reports have claimed that they have used chemical weapons on the battlefield on multiple occasions.

As the terror group fled its former capital of Raqqa in Syria, reports emerged that the group had created a “chemical weapons cell” to create large stockpiles of chemical weapons that could be deployed in the Middle East or possibly smuggled into Europe.