Calgary police have laid 128 charges against 29 people following two month-long operations targeting drug trafficking downtown — including in the city's Central Library.

Police received public complaints about drug-related activities along 17th Avenue as well as downtown along 7th Avenue S.W.

After observing drug activity near a number of family restaurants along 17th Avenue in December, police arrested seven people.

The second phase of the operation netted another 22 people, who were charged with 81 drug and criminal code offences. More than half were already known to police.

Investigators discovered people trafficking drugs in a variety of public spaces, including the Central Library and Olympic Plaza.

"Calgary's Central Library is an integral part of Calgary's downtown," said library CEO Bill Ptacek in a release.

"Like all of our 18 community libraries, it is designed to offer a safe community place that provides library services for all Calgarians within a respectful environment where lawful, civil behaviour is expected."

"The library will continue to work closely with CPS," he said.

Police made more than 30 drug seizures, chiefly crystal meth and morphine. Fentanyl was seized once.

The accused people range in age from 22 to 61.