Belgium and Britain have commemorated separate terrorist attacks committed in 2016 and 2017 the same day.
Thirty-two people were killed and more than 300 injured in three coordinated suicide attacks in Belgium on March 22, 2016 -- two at the Zaventem airport in Brussels, and one at the Maelbeek subway station in the center of the Belgian capital.
The attacks, claimed by the Islamic State (IS) extremist group, were commemorated in a ceremony at Zaventem.
In London, on March 22, 2017, five people were killed and 50 injured when a British convert to Islam, Khalid Masood, used a vehicle to run down pedestrians on the Westminster Bridge in central London before fatally stabbing a police officer on guard outside the British Parliament.
The IS group again claimed responsibility, but investigators have said they found no evidence of an association.
Following the March 22 rampage, Britain was the target of four other attacks, including three in the capital at London Bridge, Finsbury Park, and the Parsons Green subway station.
Home Secretary Amber Rudd and the leader of the House of Commons, Andrea Leadsom, said they would attend a commemorative event in Westminster Hall, inside the parliamentary complex, on March 22 to mark the anniversary.