A local resident walks across a flooded street in downtown Miami as Hurricane Irma arrives at south Florida, US, September 10, 2017. [Photo/Agencies]

MIAMI — Hurricane Irma gave Florida a coast-to-coast pummeling with winds up to 130 mph Sunday, swamping homes and boats, knocking out power to millions and toppling massive construction cranes over the Miami skyline.

The 400-mile-wide (640-kilometer-wide) storm blew ashore in the morning in the mostly cleared-out Florida Keys, then began a slow march up the state's west coast, its punishing winds extending clear across to Miami and West Palm Beach on the Atlantic side.

Irma was expected to hit the heavily populated Tampa-St. Petersburg area early Monday, though in a much-weakened state. While it arrived in Florida a Category 4 hurricane, by nightfall it was down to a Category 2 with winds of 105 mph (177 kph).

"Pray, pray for everybody in Florida," Gov Rick Scott said on "Fox News Sunday" as more than 160,000 people statewide waited it out in shelters.

There were no immediate confirmed reports of any deaths in Florida, in addition to the 24 people killed during Irma's destructive trek across the Caribbean.

Many streets were flooded in downtown Miami and other cities.

In the low-lying Keys, where a storm surge of over 10 feet was recorded, appliances and furniture were seen floating away, and Monroe County spokeswoman Cammy Clark said the ocean waters were filled with navigation hazards, including sunken boats and loose vessels. But the full extent of Irma's wrath there was not clear.

A Miami woman who went into labor was guided through delivery by phone when authorities couldn't reach her in high winds and street flooding. Firefighters later took her to the hospital.

An apparent tornado spun off by Irma destroyed six mobile homes in Palm Bay, midway up the Atlantic coast. Flooding was reported along Interstate 4, which cuts across Florida's midsection.

In downtown Miami, two of the two dozen construction cranes looming over the skyline collapsed in the wind. No injuries were reported. City officials said it would have taken about two weeks to move the massive equipment.

Curfews were imposed in Miami, Tampa, Fort Lauderdale and much of the rest of South Florida, and some arrests of violators were reported. Miami Beach barred outsiders from the island.

Fort Lauderdale police arrested nine people they said were caught on TV cameras looting sneakers and other items from a sporting goods store and a pawn shop during the hurricane.

More than 2.7 million homes and businesses across the state lost power, and utility officials said it will take weeks to restore electricity to everyone.

While Irma raked the state's Gulf Coast, forecasters warned that the entire state — including the Miami metropolitan area of 6 million people — was in danger because of the sheer size of the storm.

Nearly 7 million people in the Southeast were warned to evacuate, including 6.4 million in Florida alone.