Rio de Janeiro ? At least 2,000 police officers patrolled this coastal city Sunday and Brazilian officials pledged to host a violence-free 2016 Olympics despite bloody drug gang shootouts that left 14 people dead.

An hourslong firefight between rival gangs Saturday in one of the city’s slums killed at least 12 people, injured six and saw a police helicopter shot down and eight buses set on fire.

Police said Sunday that they killed two other suspected drug traffickers in overnight clashes near the Morro dos Macacos (“Monkey Hill”) slum where the gangs fought for territory a day earlier. But the area was largely peaceful.

Two officers died and four were injured Saturday when bullets from the gang battle ripped into their helicopter hovering overhead, forcing it into a fiery crash landing on a soccer field. Officials said they did not know if the gangs targeted the helicopter or it was hit by stray bullets.

Gunfire on the ground killed 10 suspected gunmen and wounded two bystanders.