Speaking on the sidelines of an EU summit focused on Britain's exit from the bloc, European Parliament head Antonio Tajani, who is Italian, said Paris and Rome had "diverging interests" in Libya.
"Libyans are demanding a unified European position on what is happening in their country," adding: "when I visited them, Libyans complained about different European attitudes."
France, which has oil assets in eastern Libya, has provided military assistance in past years to Haftar in his eastern stronghold, Libyan and French officials say.
Italy, the former colonial power and a big player in Libya's oil sector, has supported the U.N.-backed Prime Minister Fayez al-Sarraj.
"We need more unity, we need to speak with only one voice as Europeans, but unfortunately Europeans are divided on this," Tajani told reporters.
EU foreign affairs chief Federica Mogherini said on Monday the bloc was united in calling for a truce and a return to diplomacy in Libya.
The EU has supported al-Serraj's government in recent years to have it crack down on refugees and migrants leaving for Europe from the shores of Libya.
The EU draft statement says "hostilities must cease immediately, the LNA must withdraw and the humanitarian truces called by the U.N. must be heeded".
"The European Union... call on their international and regional partners to exert their influence and send an unequivocal message to the aggressors that there is no military solution to the crisis, only a political one," it says.