Hurricane Irma will devastate part of US: Federal agency

Irma had been a Category 5 hurricane before being downgraded to Category 4 early on Friday

The head of the Federal Emergency Management Agency said on Friday Hurricane Irma will devastate part of the United States and that US. officials are preparing a massive response to the storm.

With Irma set to hit Florida as early as Saturday, FEMA Administrator Brock Long warned at a news conference that parts of Florida would be out of electricity for days, if not longer, and that more than 100,000 people may need shelter.

"Hurricane Irma continues to be a threat that is going to devastate the United States in either Florida or some of the Southeastern states," Long said.