Angry relatives of Chinese passengers aboard the missing Malaysia Airlines plane have clashed with police outside the Malaysian embassy in Beijing.
The relatives threw water bottles at police, who had formed a human wall around the embassy gate.
Many of the protesters were pushed back and a woman who fainted was carried away on a stretcher.
About 200 family members, some in tears, had linked arms and shouted slogans including "The Malaysian government are murderers" and "We want our relatives back" as they marched to the embassy, which is about 4km from the hotel where meetings have been taking place throughout the drama.
The relatives have denounced the Kuala Lumpur government and its national carrier as "executioners", while China is demanding proof flight MH370 crashed into the southern Indian Ocean with no survivors after Malaysia announced it had gone down "beyond reasonable doubt".
Malaysian Prime Minister Najib Razak said based on fresh analysis of satellite data, it had to be assumed the plane went down in the Indian Ocean west of Australia.
In the meantime, the search for the missing plane has been suspended because of bad weather and rough seas. The Australian Maritime Safety Authority said high winds and rain meant planes could not fly safely.
The BBC is reporting British intelligence sources were told just a few days after the plane vanished that it was most likely lost in the southern Indian Ocean.
But satellite communications company Inmarsat reportedly had trouble convincing Malaysian authorities searching in the South China Sea to look further south.
The Malaysia Airlines plane vanished on 8 March after taking off from Kuala Lumpur with 239 people aboard, including two New Zealanders.
While there have been sightings of possible debris in the search area, none has yet been confirmed as having come from the plane.
The BBC reports the announcement by Mr Razak, at a news conference late on Monday night local time, came on the fifth day of an international search effort in the southern Indian Ocean.
Based on new analysis, the Air Accidents Investigation Branch in Britain and Inmarsat "have concluded that MH370 flew along the southern corridor, and that its last position was in the middle of the Indian Ocean, west of Perth", Mr Razak said.
"This is a remote location, far from any possible landing sites. It is therefore with deep sadness and regret that I must inform you that, according to this new data, flight MH370 ended in the southern Indian Ocean."
Mr Razak appealed to the media to respect the privacy of the families of the passengers and crew, saying the wait for information had been heartbreaking and this latest news harder still.
Mr Razak said the British Accidents Investigation Branch and the British-based tracking firm Inmarsat employed a type of analysis never used before to shed more definite light on the plane's flight path.
Malaysia Airlines told the families of the passengers and crew they were presumed dead.
The BBC reported the text message sent to families said: "Malaysia Airlines deeply regrets that we have to assume beyond any reasonable doubt that MH370 has been lost and that none of those on board survived... we must now accept all evidence suggests the plane went down in the Southern Indian Ocean."
The two New Zealanders on the flight were Paul Weeks, 38, who was flying from Perth to a mining job in Mongolia and Ximin Wang, 50, described on the electoral roll as a student.
Mr Weeks, who was married with two young children, moved to Perth from Christchurch two years ago, and last contacted his family from the airport lounge in the Malaysian capital. Mr Weeks' sister, Sara Weeks, asked for privacy on Tuesday as the family dealt with the latest news.
Search temporarily suspended
The search for the plane in the Indian Ocean will continue to follow up on sightings by Chinese and Australian planes of potential wreckage, described as a "grey or green circular object" and an "orange rectangular object''.
However, the search was suspended for Tuesday due to bad weather.
The Australian Maritime Safety Authority said rough seas and a forecast of gale-force winds, heavy rain and low cloud in the search area west of Perth, makes any air and sea search activities hazardous and a risk to crew.
It said the conditions had forced Australian navy ship Success to leave the area where possible debris was sighted on Monday.
The authority said it intended to continue searching for any signs of the plane once weather conditions improved.
An RNZAF Orion is among about 10 aircraft searching.
Mr Razak said Inmarsat had been able to shed further light on the plane's flight path by performing further calculations on the MH370 data "using a type of analysis never before used in an investigation of this sort".
According to Inmarsat, this involved a totally new way of modelling, which was why it took time.
The company told the BBC the new calculation involved crunching far more data, which included what other aircraft were doing at the time.
Inmarsat gave the AAIB the new data on Sunday, it said, which had to be checked before it could be made public.
Officials said earlier that the plane automatically sent an hourly "ping" - a brief signal - to the Inmarsat satellite even after other communication systems on the plane shut down.
Initial analysis showed the location of the final "ping" was probably along one of two vast arcs running north and south.
Inmarsat senior vice president of external affairs Chris McLaughlin said one of its satellites picked up a series of automated hourly "pings" from the plane that helped determine its flight path but the data could not pinpoint where the plane went down exactly.
Grief in Beijing
After the announcement, there were hysterical scenes at the hotel in Beijing where many of the relatives of those on board are staying. More than 150 of the passengers were Chinese.
People wailed, cried and dropped to the floor and a number were carried away on stretchers.
Some left the room crying uncontrollably, being held by other family members, while others wiped tears from their eyes as left the briefing. Others covered their heads, hiding their emotions.
A relative at the hotel who talked to AFP by telephone said: "We know we have no hope left now."
Some reacted with anger and suspicion after the announcement, with one woman loudly protesting that the information they had been given was untrue.
Key's 'heart goes out'
Prime Minister John Key is yet to be officially briefed on the Malaysian announcement but said New Zealand and other countries would continue to participate in the search for debris.
He said the wait for information had been difficult and his heart went out to families.
"Obviously we'll be deeply distressed for the two New Zealand families that are involved and we know this has been a very traumatic time for them and a very difficult situation because there are so many unknowns about what finally happened to the aircraft; what the motivations of it were; why the information has been so difficult to receive or to interpret so obviously my heart goes out to those families."