Three Spanish journalists are missing from the northern Syrian city of Aleppo, which has been the scene of fierce fighting between the regime and Islamic State.

The three men, Antonio Pampliega, José Manuel López and Ángel Sastre, had entered Syria from Turkey on July 10 and were last heard from two days later. Pampliega, a freelance journalist covering war zones, contributed to the AFP news agencies text coverage of Syria for a period up to 2013.

Sastre is an experienced war correspondent who regularly works with the Spanish television network, Cuatro, radio station Onda Cero and the daily newspaper, La Razón.

López has spent 11 years working as a photographer and has been a freelancer in countries such as Afghanistan, Iraq, Palestine, Kosovo and Iran since 2010. He has previously worked in Syria.

Elsa Gonzalez, president of the Federation of Press Associations of Spain, told Spanish national television on Tuesday, that "there has been no news of them since July 12. In that region there is intense fighting going on, so there is cause for concern. For the moment we can only call it a disappearance," according to Al Jazeera.

"We are now working to find them but for the time being we don't know where they are," the families of the three man said in a joint statement. The statement also asked for "as much discretion as possible" in order to help locate them, according to CNN.

A source at the Ministry of Foreign Affairs in Spain confirmed that the three men had gone missing. "We are aware of the situation and are working to solve it as soon as possible," the source said.

The Spanish government, while conceding that there were indications that the reporters had been abducted, refused to assume that they had been kidnapped. Spanish Justice Minister, Rafael Catala, said that the disappearances were "very bad news," CNN reported.

"We are very concerned about the fate of these three Spanish journalists, who disappeared in Aleppo, a city controlled partly by Islamic State and partly by Al-Nusra Front, another armed group," said Christophe Deloire, secretary-general at Reporters Without Borders. "We urge the Spanish government to use all possible means to find these journalists and we appeal to all parties to the conflict to respect the work of the media and to stop taking hostages for political ends. The UN Security Council's recent Resolution 2222 pointed out that journalists covering armed conflicts are civilians, that they cannot be deliberately targeted and that they enjoy special protection."

There is not much information about the incident, with the Syrians afraid to give details or identify themselves, fearing repercussions.

But Abu Omar al-Shimali, an anti-government activist in Aleppo Province, said he was trying to check on the missing Spaniards.

"The foreigners are not aware of the risk of being in Syria," he lamented, The New York Times reported. "Why do they keep sending foreign reporters? Every foreign reporter entering Syria is being kidnapped."