Relatives of passengers on board the missing Malaysia Airlines jetliner left their Beijing hotel to protest at the Malaysian embassy, demanding the truth from the government and an explanation from the airline. Dozens of protesters clashed with police. (Reuters)

— Days of anxious waiting and simmering anger exploded into full-blown outrage Tuesday as relatives of Chinese passengers on the missing Malaysia Airlines Flight 370 marched to the Malaysian Embassy in Beijing to demand answers.

Fueling their rage was Malaysian officials’ statement late Monday that the plane went down in the Indian Ocean and that they assumed that none of the 239 passengers and crew members survived, a conclusion that destroyed the last shreds of hope for relatives and friends of those aboard the airliner. The flight manifest listed 153 passengers on the Beijing-bound flight as Chinese.

The rowdy crowd threw water bottles at the embassy, scuffled with police, and hurled criticism, questions and curses at officials inside. Although the crowd included many relatives, several people appeared to be Chinese government agents in plain clothes whose mission seemed to be not only to guide the protest but also to keep it under control. Some relatives said they thought authorities were giving them a way to release their anger for fear that it could turn back on the Chinese government.

Despite the announcement by Malaysian Prime Minister Najib Razak on Monday night that “Flight MH370 ended in the southern Indian Ocean,” there has been no confirmed debris from the plane in the waters there. Search teams have continued to chase floating objects spotted by satellite, only to come up empty.

Under pressure to provide more evidence of how they came to their conclusion that the plane went down, Malaysian officials on Tuesday released more information describing how the British satellite company Inmarsat and the British Air Accidents Investigation Branch analyzed satellite data to conclude that Flight 370 had followed a southern route to its end.

The Australian-led search team suspended its hunt for the plane’s wreckage Tuesday because of rough weather but resumed the mission Wednesday morning. Choppy seas and long ocean swells were forecast for Wednesday and Thursday, but winds were expected to diminish from gale-force strength.

On Wednesday, aircraft and ships from six countries — Australia, New Zealand, the United States, Japan, China and South Korea — will scour three distinct areas covering nearly 50,000 square miles. In recent days, observers on low-flying planes have spotted objects in the water that could be from the plane, but until the search team can get closer to those items, the location of the jet and any of its debris remains a mystery.

At a news conference Tuesday, Malaysia Airlines chief executive Ahmad Jauhari Yahya declined to comment on the ongoing investigation into what caused the jet to veer off course.

“We do not know why,” he said. “We do not know how.”

The U.S. Navy dispatched more equipment to Australia on Tuesday. But like much of that already assembled in Perth as part of the international effort, the additional equipment will come into play only if the search area — almost three times the size of California — narrows sharply to a few dozen square miles of the ocean bottom.

NASA, whose satellites can spot objects as small as 50 feet, said it would target its satellites on the search area in the next few days.

A state-sanctioned protest

Leading up to the Beijing protest, some of the plainclothesmen corralled the protesters onto buses, provided them with well-printed placards and T-shirts bearing slogans related to the plane, and lectured them on how to protest in an orderly fashion.

What happened to Flight 370?

Many in the crowd, however, rejected the coaching, letting their most visceral emotions flow and accusing Malaysia’s leaders of lying. One woman cried, “Give me back my son,” and demanded a thorough explanation of how investigators had determined, using partial satellite data, that the plane had crashed somewhere far off the western coast of Australia.

For some families, however, the dominant question has long been whether passengers survived. With Monday’s announcement answering the question, many were beginning to focus on whom to blame.

Many in Beijing pointed fingers squarely at the Malaysian airline and government for missteps, especially in the early, most critical days of the investigation. And the Chinese government has not shied from doing the same.

Its Foreign Ministry has demanded a full accounting of how Malaysian investigators reached the conclusion that the plane crashed in the Indian Ocean. On Tuesday, according to state news media, Chinese President Xi Jinping sent a special envoy to Kuala Lumpur to deal with the issue, increasing pressure on the Malaysian government.

Chinese officials’ handling of Tuesday’s protest, in many ways, appeared to be similarly calculated.

In recent days, government officials living at a fancier hotel next to where the passengers’ families are gathered at the Lido hotel could be overheard discussing how to deal with the relatives’ emotional volatility.

Before the march on the embassy began in the morning, many unfamiliar men in plain clothes appeared at the Lido hotel and mixed in with the families. To some of the relatives — eyes still red from tears during Monday night’s traumatic revelation — the men clearly stuck out as they brightly chatted with uniformed police, surfed their smartphones and smiled.

The relatives were given matching T-shirts that read “Pray for MH370” and signs saying “We await you at home with tears” and “Please come back.”

They were led to buses outside the Lido hotel. They were told to wait for another group of families coming from another hotel. In the meantime, in one bus, a man with a loudspeaker prepared the relatives.

“We don’t have any contradictions with the Chinese government, right?” he yelled into the loudspeaker, waiting for them to yell back, “Right!” “We don’t have any contradictions with the media, right?”

One relative, from a neighboring province, said the government’s tacit approval of the protest was clear. But at the same time, he said, he was glad for a chance, no matter the circumstances, to vent his anger.

“The anger is ours, and it is real,” he said. Those more deserving of that anger than anyone else, he said, were the Malaysian authorities.

A difficult search

The search area spans 469,407 square nautical miles of water roiled this week by high winds and heavy seas, which present a challenge to spotting any floating debris from the decks of ships or aircraft.

If debris is discovered and identified as coming from the missing plane, experts will set out to determine how far it has drifted in the 18 days since it disappeared and identify a significantly smaller search area.

The additional equipment sent by the Pentagon on Tuesday included a sonar device that can be towed underwater from a boat to scan for debris and listen for a “ping” from the plane’s black box, and an autonomous underwater vehicle akin to an unmanned submarine.

The sonar is towed on a sled on a long tether that limits the towboat’s speed to less than three knots. The AUV — a Bluefin 21 — can move slightly faster. Three AUVs were used to search a 40-square-mile area of the Atlantic where an Air France airliner went down in 2009. That search took several months.

“We don’t have a debris field that we can go look for specifically,” Rear Adm. John Kirby said at the Pentagon on Tuesday. “It’s really important for everybody to understand that it’s being sent there to be ready should there be a need. And right now, there’s no need. We do not have a debris field. It’s only going to be valuable if you know you have something down there that’s worth going and taking a closer look at.”

While sonar can pick up metal objects on the ocean floor, the ping sent out by the emergency beacon attached to the black box will fall silent in a matter of days. The battery that powers it has a life of 30 days, so it is expected to die by April 7. Its signal carries for no more than three miles.

Kirby said he did not foresee the U.S. military taking a lead role in the search, “particularly not after the black box expires.”

Yang reported from Kuala Lumpur, and Halsey reported from Washington. Xu Jing, Liu Liu and Gu Jinglu in Beijing contributed to this report.