Two Italian hostages freed in Libya after two fellow captives were allegedly killed by Islamic State militants have been flown back to Italy, officials say.
The four were employees of Italian construction company Bonatti and were seized last July near the western Libyan city of Sabratha, near a compound owned by the energy group Eni.
Gino Pollicardo and Filippo Calcagno were transferred by helicopter to Tripoli from Sabratha at night and boarded an Italian plane, Libyan officials said.
They arrived at Rome's military airport of Ciampino on Sunday and were due to be interrogated by magistrates, Italian media said.
According to a spokesman for Libyan security forces in Sabratha, fellow captives Salvatore Failla and Fausto Piano were shot dead by IS militants shortly before Libyan forces attacked them on Wednesday.
The spokesman, Sabri Kshada, has said Pollicardo and Calcagno were released during a raid early on Friday.
However, the exact circumstances of both the killings and the release remain unclear. The two freed hostages have made no comment.
Sabratha is one of several Libyan cities in which militants loyal to IS have established a presence, taking advantage of the chaos that has plagued Libya since Muammar Gaddafi was toppled in an uprising five years ago.
Libya is a former Italian colony, and Rome is working with other Western powers and the United Nations to try to convince two rival Libyan governments to create a single, united coalition and focus their energy on the fight against IS.
Pollicardo and Calcagno were questioned by Libyan forces at Tripoli's Mitiga airport for about 45 minutes before departing for Italy and briefly appeared beside Ali Abu Zakouk, the foreign minister of Tripoli's self-declared government.
"We need support and cooperation from the Italians to tackle the criminal organisation of Islamic State in Libya," Zakouk said, without giving details on how the hostages were released.