In London, armed police units were used when homes were raided in Ilford and Hackney.
Sean Price, chief constable of Cleveland police, said: "Today's action strikes at the very heart of a lucrative drugs network. The aim is to take out not just street level dealers but the masterminds behind this evil trade."
Operation Sabre targeted a group which police believe has been bringing crack cocaine into the north-east of the UK from Jamaica using mainly female drug couriers.
Shipments were then moving to Middlesbrough via a rail network and then distributed across the north of the country.
The latest raid is linked to Operation Logan, an ongoing initiative involving Cleveland and Durham police designed to disrupt crack cocaine supply.
Dave Lamplough, a detective inspector with Cleveland's organised crime unit, said the operation aimed to "take out all the key players of this gang from the top downwards".
"We have had numerous strikes on members of this gang in the past but this time, armed with intelligence we have gathered over several months, we intend to stop their activities for good," he added.
The majority of those targeted in today's raids were Jamaican, with the main co-ordinators of the drug-smuggling gang based in London.
People arrested in the raids will be taken to Middlesbrough for questioning.
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