Puerto Ricans brace as tropical storm Dorian approaches

The US territory of Puerto Rico has declared a state of emergency as it braces for a tropical storm moving through the Caribbean.

The National Hurricane Center (NHC) has issued hurricane watch and tropical storm warnings for Puerto Rico and the Dominican Republic.

Forecasters expect tropical storm Dorian to develop into a hurricane in the next 24 hours.

President Donald Trump has approved an emergency declaration.

The move authorises US federal agencies to provide assistance and co-ordinate disaster relief.