(CNN) -- Family members of passengers aboard Malaysia Airlines Flight 370 faced an agonizing wait for answers, as the aircraft remained unaccounted for more than a day after it was scheduled to land.
In China, home of most of the 239 people on board, relatives of the passengers gathered in a conference room at a hotel complex in the Lido district of Beijing.
They grew increasingly frustrated Sunday as the wait continued. More than 100 people signed a hand-written petition that demanded "truth" from the airline by Sunday evening. They also urged the Chinese government to help them deal with Malaysian authorities.
More family members arrived Sunday. Video from Reuters showed Malaysia Airlines personnel in Beijing, where Flight 370 was headed, helping family members apply for expedited passports so they could fly to Kuala Lumpur early this week.
Zhang Guizhi, aunt of passenger Li Yan, told CNN that she had arrived from her native Henan province in central China and remained uncertain about how the airline would help her obtain a passport to travel to wherever the plane is found. She started crying when she mentioned that her 31-year-old niece had traveled to Malaysia with her husband and four friends for vacation.
A man who identified himself as the brother-in-law of passenger Ding Lijun said he had just arrived from Tianjin. He teared up when he said Ding had been working in Malaysia as a construction worker for a year and was taking his first trip home.
On Saturday, a young woman from the nearby port city of Tianjin broke down in tears as she told CNN that her boyfriend was on board the flight. They had plans to marry, she said.
Another woman wailed for her missing son as she was led inside.
"My son was only 40 years old," she cried. "My son, my son. What am I going to do?"
A man who identified himself as a friend of passenger Yang Jiabao showed reporters the missing man's driver's license in the hope it might help authorities find the man.
Acting Malaysian Transportation Minister Hishammuddin Hussein said he met with families in Malaysia on Sunday.
"It has been another long day. Thank you all for your thoughtful prayers. Hope will get us through the days ahead," he tweeted.
Late Saturday evening, family members met with a Malaysia Airlines delegation that had been dispatched to the Chinese capital to provide support and information. At a news conference in the early hours of Sunday, Ignatius Ong, CEO of Malaysia Airlines subsidiary Firefly and spokesman for the airline's management group, announced that immediate families should head to Kuala Lumpur.
The airline would cover their travel expenses and would fly the relatives to the plane's location "once the whereabouts of the aircraft is determined," he said.
Chinese media reported Sunday that the airline announced it would help next of kin get passports if needed and was planning to fly the first group to Kuala Lumpur on Tuesday.
With at least 12 nationalities on board, Flight 370's disappearance left families around the world reeling.
Besides the Chinese passengers -- who, according to Chinese state media, included a delegation of painters and calligraphers returning from an exhibition and a group of Buddhists returning from a religious gathering -- the flight carried passengers from Malaysia, India, Indonesia, Australia, the United States, France, New Zealand, Ukraine, Canada, Russia and the Netherlands.
The Canadians have been identified as Muktesh Mukherjee, 42, vice president of China operations for Xcoal Energy & Resources, and his wife Bai Xiaomo, 37. The couple, who once lived in Montreal, lived in Beijing with their two young boys, the Canadian broadcaster CTV reported Sunday.
The airline's manifest showed the passengers hailed from 14 countries, but later it was learned that two people named on the manifest -- an Austrian and an Italian whose passports had been stolen -- were not aboard the plane. The plane was carrying five children younger than 5 years old, the airline said.
Mei Ling Chng is believed to have been one of the people onboard. A Malaysian national who has been living in Pennsylvania since 2010, she worked as a process engineer, according to Tracy Kilgore, spokeswoman at Eastman Chemical Company, where Chng works.
"As you can imagine this has been a very shocking and sad situation, and our thoughts and prayers go out to the families of all aboard the missing flight and in particular to those of our co-worker," the spokeswoman said.
The family of Philip Wood, one of three Americans identified as among the missing, issued a statement describing him as "a man of God, a man of honor and integrity. His word was gold."
"Incredibly generous, creative and intelligent, Phil cared about people, his family, and above all, Christ," the family said. "Though our hearts are hurting, we know so many families around the world are affected just as much as us by this terrible tragedy."
Texas-based firm Freescale Semiconductor confirmed that 20 employees were passengers on Flight 370. Twelve are from Malaysia and eight from China, the company said Saturday.
"At present, we are solely focused on our employees and their families," Freescale's president and CEO Gregg Lowe said in the statement. "Our thoughts and prayers are with those affected by this tragic event."
Later, the company tweeted: "Your thoughtful words and prayers for Freescale families and friends affected by MH370 give comfort."
The company was making counselors available with around-the-clock support for employees affected by the tragedy, the statement said.
CNN's AnneClaire Stapleton, Serena Dong, Yuli Yang and Dayu Zhang in Beijing contributed to this report.