The Metropolitan Police commissioner has claimed people posing as stewards at the coronation were caught with bottles of paint they intended to throw at the parade.

In the wake of widespread condemnation of the force’s handling of the event, Sir Mark Rowley described those targeted by his officers as a “criminal network”.

He claimed police had received intelligence that people planned to use rape alarms and loud hailers to disrupt the coronation, “extensively vandalise monuments” and “throw paint at the procession”.

His defence of the police operation comes after six anti-monarchy protesters from campaign group Republic arrested during the coronation were released without charges being brought against them.

Sir Mark said it was “frustrating that there are things we are unable to share”.

“But while our investigations continue,” he added: “I can report that we found people in possession of possible lock-on devices and people that appeared to be purporting to be stewards of the event in possession of plastic bottles containing white paint which we believe were specifically to be used to criminally disrupt the procession and resulted in arrests for going equipped to commit criminal damage.”

It comes after Scotland Yard issued a statement on Sunday night expressing “regret” over the six arrests.

“Those arrested stated the items would be used to secure their placards, and the investigation has been unable to prove intent to use them to lock on and disrupt the event,” the statement said.

“This evening all six have had their bail cancelled and no further action will be taken. We regret that those six people arrested were unable to join the wider group of protesters in Trafalgar Square and elsewhere on the procession route.”

A total of 64 people were arrested during the event on Saturday, including members of Westminster City Council’s women’s safety campaign Night Stars, who hand out rape alarms and other items.