Paris' Mayor Anne Hidalgo (C) talks to emergency service members in a street in Paris centre after one person was killed and several injured by a man armed with a knife, who was shot dead by police in Paris on May 12, 2018. The attack took place near the city's main opera house. Police indicated that the attacker had been "overcome" and his motives are unknown. Pic/AFP

Islamic State, which has claimed the deadly knife attack in Paris this weekend, released a video today of a young man it claims was the attacker pledging allegiance to the jihadi group.