Darryn Frost ended his silence Saturday, telling Britain’s Press Association that he and others reacted instinctively when Usman Khan started stabbing people at a prison rehabilitation program at a hall next to the bridge on Nov. 29.

The remembrance service Monday at Guildhall Yard is meant to honor former University of Cambridge students Saskia Jones, 23, and Jack Merritt, 25, who were part of a program meant to rehabilitate prisoners.

Saskia Jones, 23, and 25-year-old Jack Merritt were fatally stabbed on Friday, and three others were injured.

Britain’s political leaders sparred Sunday over who is responsible for the early release of a convicted extremist who launched a stabbing attack in central London that left two dead and injured three.

Archibald was one of several killed during the 2017 attack, when three attackers swerved a van into pedestrians on London Bridge.

Several people are reportedly injured, and videos posted on social media depict law enforcement and emergency vehicles at the scene.

British police have arrested a third suspect in connection with the bomb that partially exploded on a London subway last week.

Britain raised its national security threat level to critical from severe on Friday, meaning an attack is expected, after a bomb on a London commuter train injured 29 people.

The assaults come after a spate of high-profile attacks, including one in which a man is accused of throwing acid at an aspiring model and her cousin as they sat in their car.

British media identified Darren Osborne as the suspect held in connection with Monday’s van attack on a group of Muslim worshippers outside a mosque in London’s Finsbury Park neighbourhood.