India's western state of Gujarat is braced for the landfall of cyclone Tauktae, which is likely to be the strongest to hit the region since 1998.

The storm has roared up India's western coast over the past two days, with six people killed and thousands evacuated.

Efforts are under way to rescue more than 400 people stranded off the coast in two commercial barges.

The cyclone comes amid a second Covid-19 wave that has overwhelmed India's healthcare system.

The meteorological department said the storm had now intensified into an "extremely severe cyclonic storm". It is expected to make landfall in Gujarat on Monday night local time, with wind speeds of up to 160km/h (100mph).

Both Gujarat and its neighbouring state, Maharashtra, are on high alert, with heavy rains also forecast.

Although Covid cases are declining in both states, the devastating effects of the nation's second wave are still being felt.

The Indian navy has said it has begun rescue operations to save the people on both of the barges, which are off the coast of Mumbai, the capital of Maharashtra.

It said it was responding to two separate requests for help - one from a barge that was adrift near an oil field about 170km from the coast, and a second from another vessel about 14km from the coast.

Three naval ships have been dispatched to help, a statement from the Indian navy said.

More than 150,000 people in low-lying areas have already been moved to shelters, sparking fears of possible new outbreaks in coming weeks. And the federal government has also ordered the vaccine drive to be halted in several coastal towns believed to be at risk.

The storm is also adding to the challenge facing India's hospitals. Mumbai has already moved 580 Covid positive patients from dedicated centres to civic hospitals as a precaution.

Officials have advised people to stay indoors - they anticipate flooded roads, damaged power lines and uprooted trees.

Thousands of fishing boats have returned to harbour, and hundreds of merchant ships have been asked to re-route.

Teams from the National Disaster Response Force (NDRF) have been deployed in both states.

Rains from the storm killed six people in Kerala, Karnataka and Goa over the weekend as the cyclone moved along the western coastline. Houses were destroyed and electricity was disrupted across several districts in these states.

The cyclone in the region in 1998 - designated 03A - killed at least 4,000 people, although the toll may have been far higher.