Forces under Haftar's command provide backing for a Tobruk-based adminstration that controls much of the east and south of the oil and gas-rich country.
Former colonial power Italy has hitherto been the strongest backer among Western allies for the UN-recognized Government of National Unity, which is based in Tripoli and sees Haftar as an arch foe.
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But that did not prevent Defence Minister Roberta Pinotti from hosting the commander, a one-time ally and later armed opponent of Libya's late dictator Moamer Kadhafi.
"The stabilization of Libya, the fight against international terrorism and the control of migration flows figured during the meeting," the defence ministry said.
Haftar also met with Italy's chief of defence staff, Claudio Graziano. Ms Pinotti reiterated Italian support for UN initiatives in Libya and urged all parties, including both Haftar and those loyal to the Government of National Unity, to reach a military solution.
The unity government has struggled to establish its authority beyond the capital in a country scarred by conflict since the 2011 NATO-backed overthrow of Kadhafi.
A life boat carries the bodies of refugees and migrants who died during the oversea journey. Photo: Aris Messinis/AFP
Amid the chaos, Libya has become a launchpad for hundreds of thousands of migrants trying to reach Europe and a base for militants aligned with the Isis group. US drone strikes launched from Italy on Sunday killed 17 people at an alleged Isis transit camp south of the city of Sirte, according to the US military.
The attacks, the first announced since US President Donald Trump took office in January, compounded hopes the Isis threat in Libya had been neutralized when the group's forces were expelled from Sirte last year. At surprise talks in Paris in July, Haftar and the unity government's head, Prime Minister Fayez al-Sarraj, agreed to a ceasefire and elections in the first half of next year.
British Foreign Secretary Boris Johnson travelled to Benghazi last month to meet Haftar and the general was in Tunisia on Monday, meeting President Beji Caid Essebsi, who offered to act as a mediator between rival Libyan factions.
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Italy has invested heavily in Sarraj's fledgling government and has said it could lead a post-stabilization peace force in its former colony.
But it has grown frustrated by the weakness of the administration and has reportedly recently turned to dealing directly with militia groups in a successful effort to stem the flow of migrant arrivals.
Libya expert Mattia Toaldo said Haftar's presence in Rome, reflected the growing influence of Interior Minister Marco Minniti, the architect of the migration strategy, "and the intelligence services who always thought the relationship with Haftar was important".
With Italian naval forces engaged in training and support of the Libyan coastguard, dialogue with Haftar takes on added importance, Toaldo added.
"Remember the threats he (Haftar) made in August about Italian ships, they've all but disappeared now."
By Angus MacKinnon