Christian Solidarity Worldwide (CSW) is calling for the release of six Egyptian Christians abducted in Libya last week.
All six of the men are from the village of Alharja South in Suhag, Egypt, and were in Libya to work.
They were abducted after being stopped at an illegal checkpoint en route from the airport to their work.
Their Libyan driver was released but the Christians were transported to an unknown location, CSW said.
It is reported by Copts United that the kidnappers are demanding 15,000 Libyan dinars (around £2,600) per captive for their release.
Hani Sadrak, whose brother and three cousins are among the victims, told Copts United that the families would have to sell their homes in order to meet the cost of the ransom.
He said he had spoken to one of his cousins on the phone, who told him that they are being held in a very small room with many other captives of different nationalities.
The cousin likened their conditions to a "living hell" and said that they have had very little food and are being beaten every day.
CSW's Founder President Mervyn Thomas said that the kidnappings were the "latest brutality" to be committed against Egyptian Christians in Libya.
He called on the authorities to take action to free the men and stamp out the targeting of religious minorities.
"The fact that these men were abducted so soon upon arrival and are being held with many other foreign nationals highlights the prevalence of kidnapping for ransom in that country," he said.
"We urge the Libyan and Egyptian authorities to intervene swiftly to secure the release of these six men and all those held with them.
"Their kidnappers must be held to account, and we call upon the international community to press those who are in power in Libya to crack down on extremist and criminal groups and address the appalling discriminatory targeting and extortion of religious minorities and refugees."
