The seabed search for the missing Malaysia Airlines jet is set to widen as a sonar scan of the most likely crash site deep beneath the Indian Ocean nears completion without yielding a single clue, authorities said on Friday.

The autonomous underwater vehicle, Bluefin-21, has so far searched 95% of the focused underwater search area, a 10km radius around the second towed pinger locator detection from April 8, with no significant results.



"If no contacts of interest are made, Bluefin 21 will continue to examine the areas adjacent to the 10-kilometer radius," officials at the search centre in Perth said in a statement.



"We are currently consulting very closely with our international partners on the best way to continue the search into the future," it added, referring to Malaysia, United States and China.

In Beijing, more than 20 relatives of MH370 passengers have been protesting outside the Malaysian Embassy since Thursday night, complaining that diplomats had not attended their meetings for the last three days and had failed to answer their questions about the plane’s disappearance.



Police closed off a stretch of the main road close to the building, but pictures posted on social media by the families showed them sitting on the kerb as they waited, having asked diplomats to come out to speak to them. Some had signs including “We want the truth” and “Do not leave, do not give up. We are waiting.” More than 150 of the passengers on the flight, which went missing after leaving Kuala Lumpur bound for Beijing on 8 March, were Chinese.

No one at the embassy could be reached for comment.

Up to eight military aircraft and 10 ships are assisting in Friday's search, covering about 49,240 square kilometres, about 1584 km north-west of Perth.



Isolated showers are expected with south-easterly winds up to 25 knots, sea swells of two to three metres, and visibility of one kilometre in thunderstorms and three kilometres in rain.

Meanwhile, Malaysia will release a preliminary report on the disappearance of flight MH370, the prime minister, Najib Razak, said.

"I have directed an internal investigation team of experts to look at the report, and there is a likelihood that next week we could release the report," Razak told CNN in an interview aired late on Thursday.

The government has so far been tight-lipped about its investigation into the disappearance of the jet, sparking anger among the relatives of the 239 people aboard the plane about the government's level of transparency.