Queen Elizabeth II has expressed her sadness over flooding and mudslides in Sierra Leone that have killed more than 300 people.

The monarch, in a message to President Ernest Bai Koroma released Thursday, says she and Prince Philip were "deeply saddened" to learn of the landslides in the capital, Freetown.

She says "our thoughts and prayers are with all who have lost loved ones and those whose homes and livelihoods have been affected."

Mudslides and flooding struck Freetown early Monday following torrential rains, with many victims trapped in homes buried under tons of mud.

Mass burials are set to begin.

The Red Cross estimates that some 600 people are still missing.