More than 1,600 people have been arrested in a county lines crackdown.
The policing minister joined an early hours raid in southeast London as forces across England and Wales took part in the “intensification week”.
It resulted in 1,660 arrests, with 80-90% expected to be charged, as well as the closure of 261 county lines and the seizure of more than £3m of drugs, 557 weapons and four XL bully dogs.
However, police chiefs were concerned by the number of children involved in what the policing minister branded as “heartless gangs”.
There was also an “unwelcome emergence” of synthetic opioids in the UK illegal drug market.
The crackdown lasted from 25 November to 2 December.
According to the National Police Chiefs’ Council (NPCC) there are around 5,500 to 6,500 county lines – the term used to describe drug dealing where mobile phones are used to supply drugs, typically from large cities to towns and rural areas, and often using children as runners.
Policing Minister Dame Diana Johnson called county lines “one of the most violent and exploitative models of drug supply”.
She added: “We are determined to stop these heartless gangs from luring young people into a life of crime.”
The NPCC said it had “safeguarded” 1,434 people over the week, almost half of which were children, by referring them to specialist support and arresting people for modern slavery offences.
Commander Paul Brogden, NPCC lead for county lines, asked parents to be more aware of what their children were doing and to report their worries to the local police if they’re concerned.
He also said there had been a “welcome shift” in the ages of children being drawn into county lines, with them “gradually getting higher”.
While the appearance of the “synthetic opioids” was “unwelcome”, Mr Brogden said it had not yet become “embedded” in the UK illegal drug market.
However, gangs were said to be “adapting to police tactics” with lines becoming “more localised”.
More than £3m of class A and B drugs, including 5.2kg of crack cocaine, 6.1kg of heroine, 33.5kg of cocaine and around 19,000 cannabis plants, were seized over the raids.
Police also seized nearly £2m in cash.
One organised crime unit arrested three people at an American sweet and vape shop – seizing a large amount of amphetamine and diazepam.
Most of the weapons found were knives and bladed weapons, but police also recovered 75 firearms and 105 other weapons including nunchucks and hammers.
Police visited over 850 addresses that had been taken over by drug gangs in a process known as cuckooing.