Hurricane Maria has strengthened to a major category three hurricane, US forecasters say, as it heads towards the Leeward Islands in the Caribbean.

It is due to hit on Monday night local time.

Maria is moving roughly along the same path as Irma, the hurricane that devastated the region this month.

The authorities fear Maria could whip up and throw the debris left behind by Hurricane Irma.

Lieutenant Colonel Paul Maynard, a Royal Marine deployed to the British Virgin Islands, told the Press Association the hurricane could pick the debris up, "spin it around, and throw it like ammunition". The UK's International Development Secretary, Priti Patel, said: "British troops, police and aid experts are working relentlessly to get help to the victims of Hurricane Irma. Those same individuals will now be tasked with also preparing for the impact of Maria."

Hurricane warnings have been issued for Guadeloupe, Dominica, St Kitts and Nevis, Montserrat, Martinique, St Lucia and the US and British Virgin Islands.

A hurricane watch is in effect for Puerto Rico, St Martin, St Barts, Saba, St Eustatius and Anguilla.

Some of these islands are still recovering after being hit by Irma - a category five hurricane which left at least 37 people dead and caused billions of dollars' worth of damage.

In its latest update on Monday, the US National Hurricane Center (NHC) said that Maria had maximum sustained winds of 200km/h (125mph).

They warned that heavy rainfall caused by the hurricane "could cause life-threatening flash floods and mudslides".

The eye of the storm is 100 miles east of Martinique, and Maria is moving west-northwest at about 13mph.

"Preparations to protect life and property should be rushed to completion," the NHC said.