Police in Sri Lanka say they have arrested almost 15,000 people during a week-long drive against drug traffickers across the country.

They say the operation led to the seizure of almost 440kg of various types of narcotics, including heroin.

Local media showed footage of officers using sniffer dogs to search homes in Colombo and other places.

Rights activists said the raids were illegal as they were conducted without search warrants.

A police spokesman told the BBC that warrants were not always required to check for drugs.

Officials say that a total of 13,666 suspects were arrested during the operation and that 1,097 addicts have been sent to a military-run rehabilitation centre.

Vehicles and property belonging to alleged criminals were also seized. Activists have said the raids targeted underprivileged neighbourhoods.

According to experts, traffickers are using Sri Lanka as a hub, and the drugs passing through the country - including heroin, hashish and cannabis - are creating serious problems.

Officials say the searches have been paused for Christmas but will resume next week.

Sri Lanka's biggest drug haul by weight was in December 2016, when police seized 800kg of cocaine.