London – The ringleader of the London attack last weekend tried to rent a 7.5-ton truck, British police have said, indicating the attackers were looking to carry out a larger-scale assault.

The UK has thwarted five plots since the Westminster attacks in March, said London police chief Cressida Dick.

“London will not be cowed by extremists who have killed 35 people in three separate attacks in Britain, but police will ask for more resources to tackle the security threats,” she added.

The attacks are domestic plans, Cressida said, adding that there are international connections and links in the last three attacks.

“Getting hold of a 7.5 ton lorry – the effects could have been even worse,” said head of London’s Counter Terrorism Command Dean Haydon.

Although ISIS has 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.

“We’re not looking for a wider network,” said Haydon, adding that officers were still trying to piece together how the three men had met.

“How did they know each other? They are a diverse bunch,” he said.

“We are highly effective at preventing attacks in this country and we will step up a gear and do our level best to stop any further attacks. But, as you point out, highly volatile people who are intent on doing something absolutely terrible and who are quite happy – maybe even pleased – to kill themselves and to use low-tech methods – these are difficult things to defend against,” Dick concluded.