ISIS supporters have been celebrating the horrific terror attacks in Brussels by launching a poll asking for suggestions for the next city to target.

On a forum page, one user set up the question poll: 'What will be the color of the Eiffel Tower in the next attacks?'

The question comes after the iconic French structure was lit up in the colours of the Belgian flag, in solidarity to the victims of the Brussels attacks.

Delay: Nelson's Column was illuminated in the colours of the flag tonight, left, 24 hours after the Eiffel Tower (right) was first illuminated

Respect: The arches of Wembley Stadium in London were also illuminated in the red, yellow and black of the Belgian flag last night

Manchester: The Town Hall was also lit up last night as a sign of solidarity to the victims of the Brussels attacks

The United Kingdom came out top on the poll for ISIS's next target with half of the supporters on the forum backing it as their top choice for a terror attack.

America and Russia were also sickeningly selected as prime targets for a terror attack, according to jihadi supporters online.

'The Islamic State will attack London, Washington, Rome and all the infidels' capitals,' tweeted one ISIS supporter.

'The Crusaders are blundered and confused. Yesterday Paris, today Brussels, and they don't know where will be the next attack,' commented another social media user.

It is not the first time that vile jihadi supporters have used social media to poll suggestions for attacks and other forms of violence.

Memorial: Tower Bridge was also lit with the French colours in support of the victims of the Paris attacks

Contrast: After November's attacks on Paris, the National Gallery was lit with the tricolore; last night only the fountains were lit with Belgian colours in Trafalgar Square

Upon the capture of Jordanian pilot Muath al-Kaseasbeh, several ISIS media activists created a hashtag in Arabic for suggestions on how to kill their captive.

#SuggestAWayToKillTheJordanianPilotPig attracted dozens of appalling ideas for murdering the Jordanian pilot, who was captured after his plane was shot down over ISIS territory 24 December 2014.

Many of the suggestions were too graphic to describe. al-Kaseasbeh was eventually filmed being burnt alive in one of ISIS's most violent propaganda videos.

London: The Belgian flag was projected on two sides of the National Portrait Gallery and the fountain in Trafalgar Square glowed red