U.S. weather forecasters are warning that Tropical Storm Irene, which is churning in the Atlantic Ocean, could strengthen into a hurricane.

The National Weather Service says the storm is about 485 kilometers southwest of Bermuda, and packing winds of about 100 kilometers per hour.

The system is traveling northwest at about 20 kilometers per hour now, but it is uncertain what path it will take and if it will make landfall.

Some information for this report provided by AP.