At least five Ecuadorian police officers were killed on Tuesday in explosive attacks in response to prisoner transfers from overcrowded penitentiaries, prompting President Guillermo Lasso to declare a state of emergency in two provinces.

The attacks overnight and early on Tuesday morning, including nine explosions in two cities, were an "open declaration of war by gangs," Lasso said in a video address.

He declared a state of emergency in Guayas and Esmeraldas provinces, where security forces will intensify operations and a curfew will come into force from 9 p.m. local time.