NEW YORK -- Sixteen journalists covering the conflict in Libya are reported missing or detained by authorities in the North African country. Three Americans are on the list of endangered journalists, compiled Tuesday by the Committee to Protect Journalists and other reports.

Two American reporters were taken into custody on April 5 by forces loyal to Libyan leader Muammar al-Qaddafi: James Foley, a photojournalist working for GlobalPost, a Boston-based news agency; and Clare Morgana Gillis, who was covering the fighting for The Atlantic and USA Today. The third American is freelance journalist Matthew VanDyke.

Foley and Gillis contacted relatives in the United States in recent days.

Gillis called her parents in New Haven, Conn., last Thursday and made a second phone call home on Tuesday. Her parents said she told them that she is being treated humanely and being held in a woman's jail in Tripoli.

"We were glad to hear from our daughter again," said her mother, Jane Gillis. "We urgently appeal to the Libyan government to let her come home immediately."

Foley had a five-minute conversation with his mother in Rochester, N.H., on Saturday. He told her that he was not injured and was being treated well. A Spanish photojournalist captured with Foley and Gillis, Manu Brabo, called his parents on Sunday to say that he was well but was being held in a Tripoli military prison.

James Bennet, editor of The Atlantic, said Monday that those working to try and win release of the journalists were relieved by the phone calls, and encouraged that it might be a sign of some headway.

"It's a terribly murky situation," Bennet said. "We did get some good news and some valuable information in those phone calls. We found out they are being treated decently."

Photojournalist Anton Hammerl was originally believed to be captured with Foley, Gillis and Brabo near the city of Brega, but Bennet said Monday it now appears Hammerl was not with them. Austria's foreign ministry said that Hammerl, who holds both South African and Austrian citizenships, may soon be allowed to call his relatives.

The mother and stepfather of a British journalist, Nigel Taylor, said Monday they were anxiously awaiting news about their son, who used to work at the BBC. Taylor went to Libya last month to work on the story and his mother said she has not talked to him since.

Taylor's mother, Jane Haviland, said she received an early-morning telephone call on March 28 but heard nothing on the other end when she answered the phone. She later determined that the call had come from Libya.

"I'm frightened," Haviland said. "I'm anxious all the time because I don't know what has happened to him. On the other hand, it is not unusual for Nigel to go weeks without calling."

Freelancer VanDyke has not spoken to his family since March 12, according to the Committee to Protect Journalists. His mother told CPJ that she received a GPS tracking email from her son on March 13 that placed him somewhere near Brega.

British journalist Kamel al-Tallou, who works for the Middle Eastern television news network Al Jazeera, is still being held in Libya, according to the network. He was captured last month along with three colleagues who have since been released.

Two journalists from the Middle East Broadcasting Corp., Mohamad al-Shuwayhadi and Magdi Hilali, are also being held in Libya, the CPJ said.

The MBC's driver is also unaccounted for, as is the driver for journalists who work at The New York Times who were captured and released.

Lotfi Ghars, a Canadian national who was working for Iran's state-run Al-Alam television news channel, was arrested on March 16 while trying to enter Libya from Tunisia, his news organization said.

There seems to be a pattern developing where foreign journalists are being targeted by forces loyal to Qaddafi for use as potential diplomatic bargaining chips, said Mohamed Abdel Dayem, program coordinator for Middle East & North Africa Committee to Protect Journalists. Often they are held near the frontlines and treated roughly by soldiers for a few days until they are transferred to the political leadership in Tripoli, he said.

The CPJ said the whereabouts of six Libyan journalists remain unclear. At least one, Atef al-Atrash, disappeared shortly after speaking on Al Jazeera from Benghazi. Other Libyan journalists reported missing are Mohamed al-Sahim, a blogger; Mohamed al-Amin, a cartoonist; Idris al-Mismar, a writer and former editor of a monthly culture magazine; Salma al-Shaab, head of the Libyan Journalists Syndicate; and Suad al-Turabouls, a correspondent for the pro-government Al-Jamahiriya.