The four-year long search for the missing Malaysia Airlines flight MH370 has formally ended.

This comes after a deep-sea search vessel completed a 90-day survey of a vast area of the southern Indian Ocean.

Malaysia's government now says it has no plans to continue the search.

The passenger plane disappeared on 8 March 2014 while flying from Kuala Lumpur to Beijing with 239 people on board. There are still fierce debates over how the flight ended.

The hunt for the missing plane formed one of the largest surface and underwater searches in aviation history.

Who conducted the search?

It has been carried out by Ocean Infinity – a US-based company.

It surveyed an area of about 80,000 sq km (30,888 sq miles), using a fleet of up to eight mini-submarines.

The deteriorating weather in the area as winter approaches now makes operating in the area impossible for the next few months.

The company had agreed to undertake the search on the basis that it would be paid only if it found the wreckage.

The search began after the likely drift patterns of parts of the plane found along the east African coast had been analysed.

It was the latest in a series of attempts to find the missing plane.

How did the flight end?

Investigators have very limited information about the plane's last hours.

Experts still cannot come to a definitive conclusion as to whether MH370 remained under the pilot's command, or crashed out of control into the sea.

Each of these two scenarios suggests different search areas.

The reasons why the pilot took the airliner off its scheduled flight path and down into a remote stretch of ocean are still unknown, as most of the communication equipment on board had been switched off.

Earlier this month, Australian investigators rejected that the plane was deliberately brought down by the pilot.