One of the suspects was identified as Maminna Alaaguir Abdel Aziz Ahmed Baba who the source said was the main perpetrator of the October 23 abduction in the Sahrawi refugee camp in Tindouf.
The second is Aghdafna Hamady Ahmed Baba, who closely aided in the kidnap. It is not clear if the two are related.
Security sources in Nouakchott and Bamako said those responsible belonged to a Sahrawi wing of the north African Al-Qaeda branch, Al-Qaeda in the Islamic Magreb (AQIM), although there has been no claim of responsibility.
Western Sahara's Polisario Front, which is fighting for the territory's independence from Morocco, said the kidnappers had come from Mali and had returned back there with the hostages -- claims rejected by Bamako.
Spanish media identified the Spanish hostages as Ainhoa Fernandez de Rincon and the Majorcan Enric Gonyalons - who was believed to be wounded during the kidnapping. The Italian foreign ministry identified the Italian as Rossella Urru, who works for the Italian Committee for the Development of Peoples (CISP).
The last news on the hostages was on October 30 when a mediator in Bamako said they were alive and being held by AQIM.
AQIM, which has its roots in Algeria, has camps in Mali which it uses as a launchpad to carry out armed attacks and kidnappings in the Sahel desert region where the group is also involved in arms and drugs trafficking.
Some hostages have ended up dead after failed negotiations or rescue efforts, while others have been released, with huge ransoms believed to be in play.
Five Europeans were kidnapped in two days less than two weeks ago.
On November 25, an armed gang snatched a Swede, a Dutchman and a man with dual British-South African nationality from a restaurant on Timbuktu's central square and killed a German with them who tried to resist, officials said.
A day earlier two French nationals described as a geologist and an engineer were taken from their hotel in Hombori 240 kilometres (150 miles) to the south, near the border with Niger.
AQIM is currently holding four French citizens kidnapped in northern Niger in September 2010.