Two Italians freed after eight months in captivity in Libya have arrived back in Italy, greeted by family members and Italy's foreign minister.

Gino Pollicardo and Filippo Calcagno arrived at Rome's Ciampino airport before dawn on Sunday.

Their return after their liberation on Friday was delayed by security concerns. Two other Italians kidnapped with them were killed Thursday during a clash between militants from the Islamic State group and local militias.

The four Italians, who were working for an Italian construction company, were taken near an industrial complex owned by energy giant Eni in the western Libyan city of Mellitah.

Italian prosecutors, as is customary, are investigating the circumstances of the kidnappings and the deaths of the two Italians.