The three Islamists who killed eight people after driving a van into pedestrians on London Bridge and then attacking nearby revelers had initially tried to hire a 7.5 tonne truck, the head of the UK capital's counter-terrorism unit said on Friday.
Commander Dean Haydon also revealed that the men had a stockpile of petrol bombs in the back of their van and carried out their deadly attack with pink ceramic knives. Officers also discovered a Koran in their safe house, opened at a page on martyrdom.
The discoveries, especially of the plan to hire a truck, suggested more could have been killed.
"Getting hold of a 7.5 tonne lorry - the effects could have been even worse," Haydon told reporters.
Although Islamic State militants have claimed responsibility for the attack, Haydon said there was no evidence the attackers - Pakistani-born Briton Khuram Butt, Italian Youssef Zaghba and Rachid Redouane who had links to Libya, Morocco and Ireland - were directed by anyone else, either in Britain or abroad.