ISTANBUL

Police in northeastern Poland said Tuesday that they arrested a dozen people and dismantled a drug-trafficking group after months of work.

Police in the Podlaskie region said in a statement that they arrested 12 and seized over 31 kilograms (68.3 pounds) of drugs, with an estimated black-market value of 1.54 million zloty ($422,026).

Stressing that all were charged with trafficking, police said eight of the detainees were also charged with participation in a criminal group, including four suspected of involvement in an armed group that has yet to be identified.

"These crimes carry a penalty of up to 15 years in prison," the police statement said.

The operation began months ago when the police uncovered a criminal drug-trafficking group in the city of Bialystok and arrested two.

One was charged with drug trafficking and remanded in custody for three months.

The other detainee was sentenced to three months in pretrial detention after being charged with trafficking a large quantity of narcotics and psychotropic substances, drug possession, and possessing a firearm without a permit after police recovered an unlicensed revolver with 26 rounds of ammunition.

After months of further investigation, 10 more suspects, including two women, were also detained.