Explosions at Zaventem Airport and Maalbeek Metro Station left more than 20 dead and dozens injured but the attacks quickly became politicised, with prominent Ukip figures and columnists quick to weigh in on the issue.
The Telegraph's Allison Pearson tweeted to say Brussels was the "jihadist capital of Europe" and asked how "remainers dare to say we're safer in the EU!"
The tweet immediately prompted a barrage of criticism, with the likes of Labour MP Chris Bryant and journalists Kay Burley and Owen Jones quick to respond.
Speaking in London, both former Labour leader Ed Miliband and former home secretary Alan Johnson said that it was inappropriate to use incidents like this for political gain:
Ukip was also quick to weigh in on the issue, with party leader Nigel Farage retweeting Pearson, adding:
Ukip defence spokesman Mike Hookem went further, saying that the attack were a "result of Schengen free movement and lax border controls", adding: "I am appalled at the loss of life and injuries. our thoughts and prayer go out to the families of those killed and injured.
"This horrific act of terrorism shows that Schengen free movement and lax border control are a threat to our security.
"The head of [Europol] said in February that 5,000 jihadists are at large in EU having slipped in from Syria.
"There are 94 returned jihadists current living in Molenbeek, Brussels. This fact alone should alert people to the fact that open borders are putting the lives of European citizens at risk."
Speaking on LBC, Ukip's London mayoral candidate Peter Whittle also linked the attacks to the EU debate.
He said: "We have to take control of our borders, this has happened as a result of people going over borders and having free movement.
"At the moment the way things stand, Our membership of the EU means we actually have a problem with our security and that is appalling."
Others, including Ukip spokesperson Michael Heaver, also joined in.
Despite the backlash against such tweets, some wondered whether there was ever an appropriate time to bring up such issues.
Emergency services continue to work in the Belgian capital to evacuate the injured and ascertain what exactly has taken place.
An emergency number has been set up for concerned relatives: +44 207 008 0000