Madrid (CNN) -- Two Spanish journalists experienced in covering wars have been kidnapped in Syria by a group linked to al Qaeda, the newspaper El Mundo said Tuesday.
The two journalists -- El Mundo staff correspondent Javier Espinosa and freelance photographer Ricardo Garcia Vilanova -- were kidnapped September 16, foreign editor Ana Alonso told CNN. Garcia was traveling with Espinosa but not on assignment for El Mundo.
After nearly three months of trying to secure their release quietly, El Mundo's top editor, Pedro J. Ramirez, said the paper, in conjunction with the family, decided to make public the kidnappings on December 10, which the United Nations designates annually as international Human Rights Day.
"Their captivity is a flagrant violation of human rights, of their free movement, and of all citizens who have the right to receive their information and images," Ramirez said at a Madrid news conference Tuesday.
Espinosa, 49, and Garcia, 42, have made numerous trips to war-torn Syria, often together, and they organized their most recent visit together, Alonso said.
Espinosa was previously kidnapped while covering a conflict in Sierra Leone, and Garcia was kidnapped last year in Syria for about 12 days, said Gervasio Sanchez, a Spanish veteran war photographer who knows both men, at the Madrid news conference. Both were subsequently released.
This time, the newspaper and families got word through intermediaries that the two men were alive and being treated relatively well as of a month ago, in the same Syrian province where they were kidnapped. Ramirez said the paper believes both are still alive, although it is not clear if they are being held in the same location.
Spain is involved in trying to secure the release of the two kidnapped journalists, but "with absolute discretion," Spanish Foreign Minister Jose Manuel Garcia-Margallo said Tuesday.
The government is in "constant contact with the families" Garcia-Margallo told reporters at an event in Madrid, the Foreign Ministry said.
Espinosa's wife, also a journalist, pleaded for the return of her husband and his colleague.
"Javier and Ricardo are not your enemy. Please, honor the revolution they protected, and set them free," Monica Prieto said during an emotional press conference in Beirut on Tuesday.
"Today we appeal to the Syrian people and all armed groups to help release Javier and Ricardo, who have always been committed to show the human face and suffering of the Syrian people during these very difficult times."
The newspaper reported the men were kidnapped at the Tal Abyad checkpoint in Raqqa province, close to the Turkish border, as they prepared to leave Syria after two weeks of coverage.
Their captors are reported to be members of a group linked to the al Qaeda-backed Islamic State of Iraq and Syria and have not revealed demands to free the two.
Initially, the captors said they wanted to ensure the two journalists were not spies, El Mundo said.
The journalists were traveling with four fighters from the Free Syrian Army, who were also kidnapped, but released 12 days later. The fighters were supposed to have provided protection to the Spaniards, the newspaper reported.
Last year, Espinosa was in the same makeshift press center in Baba Amr, Homs province, where correspondent Marie Colvin of The Sunday Times of London and French photographer Remi Ochlik were killed.
El Mundo reported an activist from Homs contacted the al Qaeda-linked captors to plead, unsuccessfully, for the release of the two Spanish journalists, telling them that Espinosa had helped evacuate wounded from Baba Amr last year.
Another longtime Spanish war correspondent, Marc Marginedas, 46, was kidnapped in Syria on September 4, apparently by jihadi combatants near the city of Hama, his newspaper, El Periodico de Catalunya, reported on September 24.
CNN's Nick Paton Walsh contributed to this report.