Two Italians who had been kidnapped in Libya and held in the western coastal town of Sabratha have been killed, the Italian foreign ministry has said as it begins investigations into their deaths.

Although the identity of the two construction workers, Fausto Piano and Salvatore Failla, has not been definitely confirmed, Italian authorities said they have informed the families of their deaths.

Reports of their killings followed images shared on social media appearing to show the pair dead. In a statement to IBTimes UK the Italian foreign ministry has said it had reasons to believe the two "western-looking" victims of a shooting in Sabratha region shown in an online video were Piano and Failla.

"Their families have been informed," the ministry said , adding the information was still being verified but the process was difficult as authorities have no access to the bodies.

Piano and Failla were kidnapped from the Mellitah oil and gas installation in July of last year along with two other workers from Italian construction company Bonatti, Filippo Calcagno and Gino Tullicardo.

At the time the Italian government said it believed the kidnapping to be related to extortion rather than by Islamic State or other ideologically motivated groups operating in the North African country.

The offshoot of Islamic State (Isis) in Libya beheaded 12 security officials in Sabratha on February 24 and killed seven others, following heavy clashes in the coastal town.

Daesh (IS) forces were forced back, but not before they exacted their grisly revenge on the town's security forces, apparently in retaliation US air strikes on Qasr Talil that killed at least 30 Daesh fighters.

The bombing targeted Tunisian national Noureddine Chouchane, who helped organise the Sousse beach massacre and the Bardo Museum attack. Two Serbian diplomats, also held hostage, were believed killed in the same air strikes.