By Anthony Faiola and Catarina Fernandes Martins

July 7, 2023 at 1:00 a.m. EDT

Tourists visiting Porto, Portugal, pass people using drugs at the Mouzinho da Silveira fountain in June. Some areas in the city center with visible drug use are near heavy tourist foot traffic. (Demetrius Freeman/The Washington Post)

PORTO, Portugal — Addiction haunts the recesses of this ancient port city, as people with gaunt, clumsy hands lift crack pipes to lips, syringes to veins. Authorities are sealing off warren-like alleyways with iron bars and fencing in parks to halt the spread of encampments. A siege mentality is taking root in nearby enclaves of pricey condos and multimillion-euro homes.

Portugal decriminalized all drug use, including marijuana, cocaine and heroin, in an experiment that inspired similar efforts elsewhere, but now police are blaming a spike in the number of people who use drugs for a rise in crime. In one neighborhood, state-issued paraphernalia — powder-blue syringe caps, packets of citric acid for diluting heroin — litters sidewalks outside an elementary school.

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