The British territory of Bermuda is under a tropical storm watch as Hurricane Bertha approaches.

The U.S. National Hurricane Center issued the advisory Friday, and says the storm is already producing large swells and high surf in Bermuda.

Meteorologists said Bertha is about 500 kilometers south of Bermuda as of Friday morning, and has wind speeds of up to 220 kilometers per hour.

Residents of the island, located off the southeast coast of the United States, are being advised to monitor the storm's progress closely.

Bertha is the first hurricane of the 2008 Atlantic hurricane season, which began June 1 and ends November 30.

Some information for this report was provided by AP and Reuters.