QUITO, Ecuador (AP) — Gunfire and a subsequent explosion left at least five people dead, 15 injured and several others missing, as well as damaging homes, in the Ecuadorian port city of Guayaquil, authorities said Sunday.

On its Twitter account, Ecuador's Prosecutor's Office said its agents were gathering evidence to establish the cause and motive for the attack in Guayaquil's Cristo del Consuelo neighborhood.

Interior Minister Patricio Carrillo tweeted that organized crime in Ecuador is now attacking with explosives.

Sunday's violence “is a declaration of war against the State. Either we unite to face it or the price will be even higher for society," he wrote.

Guayaquil, 270 kilometers (168 miles) southwest of the capital Quito, has seen frequent shootings and killings by members of rival gangs believed to have links to national and international drug trafficking. Dozens were killed last year in massacres inside the largest state prison in the city.