The damage from Hurricane Milton becomes apparent as the storm moves into the Atlantic Ocean

Florida authorities began assessing the damage caused by Hurricane Milton's passage through the state early Thursday, as the storm moved into the Atlantic Ocean after a night of strong winds, torrential rain and storm surge.

Milton made landfall on Florida's Gulf Coast late Wednesday as a Category 3 hurricane. It came ashore with winds of 100 miles per hour and spawned dozens of tornadoes. More than 3 million energy customers in Florida were without power early Thursday, according to the website PowerOutage.us.

The tornadoes along Florida's Gulf Coast proved deadly. “We lost some lives,” St. Lucie County Sheriff Keith Pearson told WPBF News, an ABC News affiliate in West Palm Beach. Pearson did not say how many were killed.

About 125 homes were destroyed before the hurricane came ashore, many of them mobile homes in senior living communities, said Kevin Guthrie, director of the Florida Division of Emergency Management.

The National Hurricane Center said Thursday that the storm caused “significant flooding and damaging winds in its vicinity.” As of 5 a.m. ET, the NHC said the worst conditions had shifted to east-central and northeast Florida.

Dramatic photos and videos emerged overnight as Milton crossed into Florida. City authorities said winds of 90 miles per hour ripped through downtown St. Petersburg, causing a crane to collapse at a construction site there. No injuries were reported, but videos from the scene showed damage to surrounding buildings.

The wind also tore off part of the roof of Tropicana Field stadium in the city. Capt. Garth Swingle of St. Petersburg Fire Rescue told ABC News they are in contact with people sheltering inside and are safe.

Milton also caused a major water main break that affected drinking water supplies throughout the city. The subsequent closure is expected to last until necessary repairs can be completed, officials said.

North of Tampa, authorities received more than 140 calls about road disruptions, according to the Pasco Sheriff's Office. The emergency services “are working to eliminate these threats as quickly as possible,” the office wrote on X.

The Hillsborough County Sheriff's Office reported significant storm damage to a 7-Eleven store northwest of Tampa. Sheriff Chad Chronister warned of downed trees and power lines in the county. Chronister asked residents to stay indoors while emergency crews cleaned up the damage.

This is a developing story. Please check back for updates.

ABC News' Victoria Arancio and Ahmad Hemingway contributed to this report.