European police have dismantled a major synthetic drug manufacturing network operating illegal labs across several EU countries.

Polish authorities said more than 9.3 tonnes of drugs were seized, over 100 suspects arrested, and 24 large-scale laboratories shut down.

The yearlong operation, coordinated by Europol, involved police from six countries and targeted a network centred in Poland.

Investigators also seized around 1,000 tonnes of chemicals imported from China and India that were used to produce drugs such as MDMA, amphetamine and meth, Al-Jazeera has reported.

Europol said the crackdown delivered the largest-ever blow to organised crime groups involved in synthetic drug production and distribution.