Born of tribal origin in Saudi Arabia, stateless people known as bidoons live on society's margins, unable even to register marriages or open a bank account because they lack identification cards.
"Our life is frozen, suspended. We don't have access to services or medical care," complained Abu Ibrahim, 50, as he sat on a floor covered with a modest carpet, an old air conditioner humming in the background.
"There is discrimination in this country," he said, pointing to the privileges available to Saudi citizens that the bidoons cannot enjoy.
Traditionally, the nomadic tribes roamed the Arabian desert, but when Arab states were formed in the last century, newly established borders limited them to their respective countries.
Many were not accorded the nationalities of the new states, apparently for failing to register.
The problem of the stateless is "chronic," said Saudi rights activist Walid Abulkheir. "They live in miserable conditions, and life is very difficult for them."
He said that many of the nomadic tribesmen "made a mistake by not registering with authorities, due to being on the move."
But he said that the stateless also include naturalised Yemenis who were stripped of their Saudi passports after Sanaa backed Iraq following its invasion of Kuwait in 1990.
A stateless fruit seller of Yemeni origin died in May after setting himself alight in protest at the seizure of his stock by officials for selling without a permit in Riyadh.
Authorities in oil-rich Saudi Arabia decided 13 years ago to grant citizenship to members of the stateless tribes, but some 70,000 people remain stateless, according to the UN High Commissioner for Refugees (UNHCR).
Many even lack the so-called black card which gives them a social security number that provides access to services.
"My children have graduated from university, but they are unemployed, and my daughters will not be able to get married legally because they don't have that number," said Abdullah, 60, who declined to give his full name.
A government commission held a census in the late 1970s of tribal groups who were still stateless. Those counted were given the black card that they have to renew in Hafr el-Batin, in the northeast, every five years.
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"Anyone forgetting to renew the card faces a lot of problems," said legal consultant Ahmed al-Anzi.
He said the use of technology in government has worsened things for the bidoons, because a person without the computer-generated number "does not officially exist."
A bidoon is like "someone living in a glass box: he sees the world moving around him but he can't do anything," Anzi said, describing the crippling constraints imposed on them.
Even for those stateless who do have the special card, life remains a struggle, according to Nasser al-Shammari.
"It's not easy for those people to get a passport to travel for treatment or study. Sometimes they get a travel document that can be used only once, and it does not entitle them to travel to neighbouring Gulf countries," he complained.
Cardholders are also not allowed to own property or more than one car.
Renewing the black card takes months, Shammari said, pointing out that during this process, holders lose access to their own bank accounts and are even banned from driving.
"This means your life goes on hold," he said.
The issue of stateless people is not exclusive to Saudi Arabia: other Gulf states have similar situations.
Kuwait, for example, has more than 106,000 bidoons.
Born and raised in the emirate, they demand Kuwaiti citizenship, but the government says that only 34,000 of them qualify, and that the rest hold other nationalities.
Kuwait's parliament in March passed a bill granting citizenship to 4,000 foreigners, but without specifying whether the beneficiaries would be bidoons or not.
There are also an estimated 10,000 stateless people in the United Arab Emirates.