The mayor of the island's biggest city, San Juan, has said the response to the disaster is "not a good news story".

The Trump administration has declared that its relief efforts in Puerto Rico are succeeding, but people on the island said help was scarce eight days after Hurricane Maria devastated the US territory.

Puerto Rican officials could not reach more than half their towns amid a push to evacuate tens of thousands of people over a failing dam as the disaster wrought by Hurricane Maria becomes clear.

A failing dam has sparked emergency evacuations of two towns in north-west Puerto Rico as the US territory struggled with flooding, an island-wide blackout and other dangers in Hurricane Maria's wake.

More than 15 people are dead and 20 remain missing after Hurricane Maria's direct hit on Dominica, the prime minister has said.

Rescuers are hard at work today after Hurricane Maria ravaged Puerto Rico, knocking out electricity to the entire island and triggering landslides and floods.

The strongest hurricane to hit Puerto Rico in over 80 years destroyed hundreds of homes, knocked out power across the entire island and triggered heavy flooding on Wednesday.

The International Space Station's Joe Acaba, the first astronaut of Puerto Rican heritage, has been affected by two hurricanes - even in orbit.

Frightening.

Hurricane Maria has intensified into a "potentially catastrophic" category five storm as it continues on a collision course with Caribbean islands already battered by Irma.