The relatives had previously been given regular updates on the search for the plane by airline officials at a hotel in Beijing. But the briefings were cancelled last month, to the fury of many who say they no longer have any way of making their voices heard.
Relatives organised a visit to the Beijing office of the airline to "demand answers", a message posted on their official online account said, but were turned away and refused access to airline staff.
"I came here today to get answers but I am not allowed to see anyone," said Dai Shuqin, who added her younger sister was on the plane.
As relatives around her collapsed onto the floor, crying in each others arms, Dai then began shouting: "I only want to find foreign journalists. I have a lot things to say to them. I want the whole world to find out what we're encountering."
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The visit to the airline's Beijing office was planned as Chinese families prepare to mark 100 days since the plane disappeared on June 16. In China, the mourning period for deceased loved ones commonly lasts for 100 days.
"I am over 40 years old and I never knew the true meaning of suffering before. But over these past three months, I now know its meaning," added Jiang, whose 70-year-old mother was on the plane.
A woman answering the phone at the airline's Beijing office refused to comment when contacted by AFP.
Meanwhile, French businessman Ghyslain Wattrelos, whose wife and teenage son and daughter were on the plane, said in an interview with French Europe Radio 1 that he is convinced foul play was involved in the plane's disappearance.
"We get the impression that they (the authorities) are hiding something," he added.