In a statement late on Monday, the House of Representatives based in the eastern port of Tobruk said Egyptian backing was needed to stave off what it described as a Turkish invasion and occupation.
The statement underscores the growing stakes in Libya, where battle lines solidified earlier this month near the city of Sirte, after the GNA and Turkey drove the eastern-based Libyan National Army (LNA) back from a yearlong assault on Tripoli.
Libya has been divided since 2014 between the GNA in Tripoli and a rival eastern administration in Benghazi, where LNA commander Khalifa Haftar has dominated. There is also a separate House of Representatives based in Tripoli.
Any major new escalation could risk igniting a direct conflict in Libya among the foreign powers that have already poured in weapons and fighters in violation of an arms embargo. The LNA is backed by the United Arab Emirates, Russia and Egypt.
Egyptian President Abdel Fattah el-Sisi has already warned the army might enter Libya if the GNA and its Turkish allies renew an assault on Sirte, a central coastal city seen as the gateway to Libya's main oil export terminals.
Control over oil, the main source of state revenue, has emerged as the biggest prize in the conflict, with eastern forces having imposed a blockade on production and exports since January.
Under international agreements, only the National Oil Corp (NOC) based in Tripoli has the right to produce and export oil, while revenues must flow to the Central Bank of Libya, also located in the capital.
On Friday international diplomacy led by the United Nations and the United States appeared to have ended the oil blockade when a first tanker was allowed to dock at Es Sider and load with oil from storage.However, the LNA on Saturday said it was reimposing the blockade, a decision that the oil company NOC blamed on the United Arab Emirates. The UAE said it wanted a swift resumption of Libya oil exports but only if some conditions were met.