Three people were arrested as police raided properties in search of drugs and weapons ahead of the Notting Hill Carnival.
The dawn raids in west London were part of the four-week Operation Razorback which targets people intending to commit crime during the street party.
Ten homes in Notting Hill, Ladbroke Grove and Fulham were searched.
Those arrested are being held on suspicion of money laundering and drugs offences.
Ch Insp Chris Allmey said 72 people had been arrested and drugs and weapons seized since 2 August.
'Gangs settle scores'
Four teams searched homes in Hillman Drive, Shrewsbury Street and a sixth floor flat at the Peabody Estate, in north Kensington, and a flat in Redwood Court, Fulham.
One person is being held on suspicion of intent to supply class A drugs, a second on suspicion of money laundering and a third on suspicion of possessing cannabis.
The operation, which will continue up until the carnival, has been extended by two weeks this year.
Mr Allmey said: "It's aimed at deterring and disrupting people who are intending to attend carnival to commit crime and disorder. It is intelligence-led so we are using information provided by the community.
"Notting Hill Carnival is a wonderful event which has got a world-wide reputation, we want it to stay safe. Unfortunately there are people who use it as an opportunity to commit crime and gang members use it as an opportunity to settle old scores."
Since the start of the operation, Metropolitan Police officers have carried out 40 search warrants, resulting in 69 arrests, and recovery of Class A and B drugs, weapons - including knives and a BB gun - and £60,000 cash.
More than one million people are expected to attend the carnival at the end of August.