BOGOTA, Colombia (AP) — A power blackout Wednesday hit several large cities near Colombia’s Caribbean coast that are experiencing an uptick in coronavirus cases, raising worries about operations at hospitals treating COVID-19 cases.

The mayor of the popular tourist destination of Cartagena warned residents in a video posted online that water service could soon be cut off as a result of the blackout and urged peole to collect water as quickly as possible.

“The lights are out in all the coast,” Mayor William Dau Chamat said. “The cause is still not known — and while it could be resolved shortly, it could also continue for some time.”

Electrical provider XM said in a statement only that “an event” at 2:27 p.m. had knocked out power for several areas. By late Wednesday, authorities reported that nearly 90% of the region's electricity had been restored.

Cities including Cartagena and Barranquilla have seen a recent surge in COVID-19 cases, sparking concern for patients in hospitals.

Barranquilla had 9,250 confirmed cases Wednesday, including 108 patients in intensive care units, according to Colombia’s National Institute of Health. Cartagena, which has a slightly smaller population, had 6,583 cases, including 71 patients in ICUs.

Dionne Cruz, president of the Colombian Association for Public Health, said initial reports indicated that all hospital power plants were functioning, but she called on the government to ensure they have a steady supply of fuel if needed.

“They don’t have a long-term capacity,” she said. “This needs to be resolved quickly.”

She also expressed concern that no power while in hot weather could lead many people to break lockdown rules and leave their homes to escape the heat.