Four men - three Spaniards and a Turk - were arrested yesterday at a toll station on the AP-6 near Adanero (Ávila) after they were found to be transporting 21.5kg of high-grade heroin for distribution in Valladolid and throughout the rest of the Castilla León region.

A National Police spokesman estimated the street value of the haul at at least three million euros, depending on how it was cut.

This is the second phase of an investigation into two gangs trafficking Turkish heroin that started last February.

Last August, seven individuals were detained in a raid on a property in Parla (Madrid), where a further 11kg of heroin were seized.

Among those arrested on that occasion were the two alleged gang leaders - an Iranian and a Turk - as well as three Spaniards and two Rumanians.