Anti-regime protesters hold up pictures of missing relatives as they greet U.N. observers in the village of Azzara on May 4, 2012.
- An activist group says it has the names of 18,000 people reportedly kidnapped
- It says it knows about another 10,000, but families won't divulge their names out of fear
- CNN cannot independently confirm reports of kidnappings or the overall toll
- The activist group Avaaz says it will present testimonies to the U.N. Human Rights Council
(CNN) -- On his way to buy heating fuel, a Syrian farmer reaches a military checkpoint and is snatched up by government forces.
A man known for his peaceful activism is dragged out of his home in front of his wife and young children.
And a young man cries every day, fearing for the worst for his missing brother.
According to the international activist group Avaaz, the tales represent a tiny fraction of the thousands of Syrians who have been kidnapped by Syrian government forces in the past 19 months.
"Syrians are being plucked off the street by Syrian security forces and paramilitaries and being disappeared into torture cells," Avaaz Campaign Director Alice Jay said in a statement. "This is a deliberate strategy to terrorize families and communities -- the panic of not knowing whether your husband or child is alive breeds such fear that it silences dissent."
Renewed bid for Syria solution

A mother holds her wounded daughter as she waits for treatment at the Dar al-Shifa hospital in the northern city of Aleppo, as fighting in Syria's second largest city continues.
A fighter injured in the Arqub neighborhood of northern city of Aleppo is brought to a hospital on October 1, 2012, as fighting in Syria's second largest city between rebel forces and government troops continues.
Three car bombs destroyed the area around a military officers' club and a hotel in Aleppo, Syria, on Wednesday, October 3. At least 40 people were killed and 90 wounded, most of them soldiers, a monitoring group said.
Car bomb explosions in Aleppo on Wednesday left a crater in the ground.
Friends lay a rebel fighter on a gurney after he was shot in the chest during heavy battles in the Midan neighborhood on Monday, October 1.
A nurse helps treat a 7-year-old girl who's neck was badly wounded by shrapnel at the Dar Al Shifaa hospital in Aleppo on Monday, October 1.
A doctor looks at the register of dead people, stained with blood, in a hospital in the eastern sector of the city of Aleppo on October 1, 2012.
A Syrian rebel ducks for cover during clashes to control the area around the Zacharias mosque in the old city of Aleppo.
Men carry the covered body of a child killed in an attack by Syrian government forces in Aleppo on Friday, Spetember 28.
Syrians inspect damages in the old city of Aleppo after the area was shelled by Syrian regime forces on Sunday.
Smoke billows from a burning textile factory after Syrian regime forces shelled a nearby position held by rebels in the Aleppo neighbourhood of Arqub Sunday.
Rebel fighters gather as they hold their position some 50 meters away from Syrian government troops during fighting in Aleppo's northern Izaa quarter on Thursday, September 27.
A Syrian rebel mans a machine gun near Al-Bab, northeast of Syria's second city Aleppo.
In pictures: Fighting in Aleppo
In pictures: Fighting in Aleppo
In pictures: Showdown in Syria
In pictures: Showdown in Syria
In pictures: Showdown in Syria
In pictures: Showdown in Syria
In pictures: Showdown in Syria
In pictures: Showdown in Syria
In pictures: Showdown in Syria
In pictures: Showdown in Syria
In pictures: Showdown in Syria
In pictures: Showdown in Syria
In pictures: Fighting in Aleppo
In pictures: Showdown in Syria
Syrian rebels say they shot down chopper
Syrian jihadists getting weapons
Avaaz reports that at least 28,000 have been "forcibly disappeared." The group uses that term to conform to language used in the International Convention for the Protection of All Persons from Enforced Disappearance, which defines it as kidnapping by someone acting on behalf of a state.
Avaaz, which promotes activism on human rights and other issues, based its report on information provided by human rights lawyers.
Among them is Fadel Abdul Ghany, who said his group, the Syrian Network for Human Rights, has the names of 18,000 people who are missing. The network reportedly has information about 10,000 other cases, but does not have names because families have been too scared to divulge them.
Abdul Ghany told CNN his group updates its figures if it learns that a reported person is no longer missing or has died.
"Those missing people are still missing, and no one (has) heard anything from them or about their situation, including families, activists or legal entities," he told CNN.
CNN cannot independently confirm reports of kidnappings or the overall number, as the Syrian government has restricted access by international journalists.
Avaaz said it will present testimonies from friends and relatives of those missing to the U.N. Human Rights Council in hopes of an investigation.
Some relatives said they rely on second- or third-hand information for clues on what happened to their loved ones.
Amer Abdullah, a 32-year-old from Idlib province, said security forces choked off supplies of heating fuel after demonstrations began in his area.
Abdullah told Avaaz that his brother, who tried to get fuel for the neighborhood, was stopped and arrested at a military checkpoint.
"Since then, we do not know anything about him except from recently released detainees. We last heard about him three months ago. We were told that he was in the prison of Mazzeh, physically weak and that he lost a lot of weight," Abdullah told Avaaz. "We still don¹t know in which security branch he is being held. We did not dare to go and ask about him for fear of being arrested."
As of late Thursday morning, the Syrian government had not acknowledged the Avaaz report through state-run media. Syrian President Bashar al-Assad's government has consistently said it is fighting "armed terrorist groups" and is trying to secure the country.
Fighting continues in the country. At least 47 people have been killed Thursday, the opposition Local Coordination Committees of Syria said.
CNN's Yousuf Basil contributed to this report.