Flames and smoke billow as firefighters deal with a serious fire in a tower block at Latimer Road in West London, Britain June 14, 2017. [Photo/Agencies]

LONDON - A massive fire engulfed a 27-story apartment building in western London early Wednesday three hours after police received the first report of the blaze.

At least 30 people were taken to hospital, the ambulance service said.

"We can confirm that we have taken 30 patients to five hospitals," London Ambulance Service said.

The Grenfell Tower on the Lancaster West Estate, built in the 1970s and renovated several times, contains 120 homes. It is feared many are trapped inside the blazing building as the fire broke out in the wee hours of Wednesday.

Live broadcast by SkyNews showed one side of the building totally blackened, with heavy smoke billowing into the air.

Local reports cited witnesses as saying they saw people jumping from the building to escape the fire and they heard screams for help as well.

The London Ambulance Service said earlier it sent "a number of resources."

Currently, there are 40 fire engines and 200 firefighters working on the scene. A latest twitter feed by the London Fire Brigade declared the fire a major incident.

The Metropolitan Police have closed major road A40 due to the fire and asked people to avoid the area so as to allow emergency services to get to the scene.

Police received report of the fire at the building at 1:16 am local time (0016 GMT).