"We are making significant progress in identifying the three attackers, and that there were no other suspects at the scene, when the attack was carried out. Work is ongoing to understand more about them, their connections and whether they were assisted or supported by anyone else," Rowley said, as quoted in a statement published on the police website.
The police confirmed that the perpetrators had used a rented car during the attack.
"We have established that the van used during the attack, a white Renault van — was recently hired by one of the attackers," Rowley said.
According to the local authorities, at least seven people were killed and 48 more injured.
Rowley said that eight police firearms officers had confronted the attackers.
UK Metropolitan Police said later on Sunday that 12 people had been arrested during raids in East London following recent attacks.