As Tropical Storm Florence moved closer to the East Coast on Sunday morning, it strengthened into a full-blown hurricane threatening the North and South Carolina, as well as the Mid-Atlantic, the National Oceanic and Atmospheric Administration said.

The category 1 hurricane had maximum sustained winds of 75 mph with higher gusts as of Sunday morning. The center of the storm was around 750 miles southeast of Bermuda and was moving west at 6 mph, according to the National Hurricane Center.

Hurricane-force winds extended from the storm's center up to 15 miles and tropical-storm-force winds extended up to 115 miles, the hurricane said.

By Monday, the storm would further strengthen into a major hurricane and remain extremely dangerous through Thursday, when it is forecast to reach the southeastern U.S. coast, the hurricane center predicted in a 11 a.m. ET Sunday bulletin.

Storm swells created by Florence were already affecting Bermuda and were beginning to reach parts of the U.S. East Coast, the hurricane center said Saturday. The swells are likely to create life-threatening surf and rip current conditions, NOAA said.

Multiple East Coast governors began warning their states Saturday to prepare for the storm.

South Carolina Gov. Henry McMaster declared a state of emergency as reports came in that Florence was expected to strengthen into a hurricane.

He warned residents of the state to prepare their homes and property immediately for the incoming storm as it appeared unpredictable and unusual compared to past storms and maintained a steady path toward South Carolina's coast.

"We do not know when it will change or if it will change, but we are preparing for the worst and, of course, hoping for the best," McMaster said Saturday at a news conference. "But being prepared is always the best strategy."

North Carolina Gov. Roy Cooper also declared a state of emergency for his state, but his larger concern was for farmers. The governor signed an executive order that waived service hour and weight limit restrictions on trucks carrying crops and livestock.

"While it's still too early to know the storm's path, we know we have to be prepared," Cooper said. "During harvest, time is of the essence. Action today can avoid losses due to Florence."

Here are the 5 PM AST Sep. 8 Key Messages for Tropical Storm #Florence. https://t.co/M0WpomITcx pic.twitter.com/U4GJxsOruA — National Hurricane Center (@NHC_Atlantic) September 8, 2018

Virginia Gov. Ralph Northam declared a state of emergency Saturday in advance of the storm.

"Forecasts increasingly expect the storm to strengthen into a major hurricane that could seriously affect the East Coast and Virginians," Northam said in a statement. He said that while the path is uncertain, the state could see flooding, high winds and a potential storm surge this week.