At least 23 people have been killed in the explosions which took place in Brussels earlier today, and 35 severely injured.
Travel across the Belgian capital has since been suspended.
In the UK, security has been increased at both London Gatwick and Heathrow airports.
A spokesman for Gatwick Airport said the safety of passengers and staff was the "absolute priority".
He added: "As a result of the terrible incidents in Brussels we have increased our security presence and patrols around the airport."
Heathrow issued a statement which read: "In the light of events in Brussels airport we are working with the police at Heathrow who are providing a high visibility presence."
Meanwhile British Airways have taken to Twitter to update travellers on flights, revealing that two have been cancelled this morning.
Eurostar have also taken to Twitter to announced that all services to and from Brussels has been suspended.
Customers have been advised not to come to the station and to exchange their tickets.
Anyone concerned about family and friends can contact the Foreign Office helpline on +44 207 008 0000.
It was reported yesterday that police in London have prepared for 10 simultaneous terror attacks across the capital.
According to The Sunday Times, an unnamed minister was quoted as saying: “We used to plan for three simultaneous attacks but Paris has shown that you need to be ready for more than that.
“We are ready if someone tries with seven, eight, nine, ten.”
It has now been confirmed that police forces across the UK have increased their presence in key locations in response to the attacks in Brussels.
However the Mayor of London has stressed that there is no intelligence to suggest any imminent terrorist threat to the UK's capital.
We will bring you more on this story as it develops.