Photo of the Mandarin Oriental Hotel, London, ablaze on fire.

A massive fire broke out in five-star Mandarin Oriental Hotel in Knightsbridge, London, just a week after £185 million restorations were completed.

Witnesses saw smoke rising from the building just before 4 pm local time.

Thirty-six hotel guests and 250 staff members were evacuated.

The blaze affected several floors but was quickly extinguished by the London Fire Brigade.

Restorations to the hotel had begun 18 months prior and cost an estimated £185 million, including public areas, dining spaces and over 180 guest suites.

The cause of the fire is still unknown.