The Pacific island nation of Fiji was hunkering down Saturday as a formidable cyclone with winds of 300 kilometers (186 miles) per hour bore down.

Cyclone Winston was forecast to pass between the two main populated islands overnight. Many domestic and international flights had been canceled and authorities were urging people to secure their homes and not venture outside.

Fiji's Prime Minister Voreqe Bainimarama wrote on Facebook Saturday that the island's evacuation centers were operational and the government was prepared to deal with a potential crisis.

"As a nation, we are facing an ordeal of the most grievous kind," he wrote. "We must stick together as a people and look after each other."

He said he was concerned some people in the cities weren't taking the threat seriously enough.

The U.S. Joint Typhoon Warning Center said gusts from the cyclone were reaching 360 kph (224 mph).

The Fiji Times newspaper reported some damage, including a roof being blown off one home, from some of the nation's smaller islands to the east as the cyclone began to strike there.

The Times said there had been a run on supermarkets and stores as people stocked up on essential supplies and that a 5 p.m. curfew had been placed on all public transportation, including busses, minibuses and taxis.

Many people were hoping the cyclone's path would remain as forecast and thread between the islands of Vanua Levu to the north and Vitu Levu to the south, which is home to the capital Suva, so that both islands would avoid a direct hit.

Fiji is home to about 900,000 people.