Counter-terror police are leading the investigation, but the incident “has not been declared as terrorism” at this stage, the Metropolitan Police said in a statement on Friday.
Cdr Helen Flanagan, head of Counter Terrorism Policing London, said: “Since this appalling attack last week, we have been working continuously to investigate and identify those responsible.”
She said the support from the local community since the attack took place had been “incredible”.
Police patrols have been stepped up in areas with large Jewish populations following the attack.
“We know that local community concerns continue to remain high – particularly for our Jewish communities in the Passover festival period,” Det Ch Sup Luke Williams, who is in charge of North West London policing, said.
He emphasised that the presence of additional officers were “precautionary measures and not in response to any specific threat”.