Local media in Brazil are reporting more than 30 people have been shot dead in the northern city of Belem since the weekend.

The G1 news portal says 33 people have been killed since Sunday, when police officer Maria de Fatima dos Santos was gunned down.

The Brazilian think tank Igarape says Belem averaged 2.5 homicides a day last year, a rate less than a third of this week's.

The state's Public Security Department said Wednesday it could not confirm the number of dead.

Authorities in Latin America's largest nation are often slow to confirm killings, and most homicides go unsolved. But with security issues top of mind for many Brazilians, local media often cover deaths closely.

Many killings involve shootings between drug gangs or shootouts between gangs and police.