Egypt's President Abdel Fattah el-Sisi has warned of direct military intervention in Libya if Turkish-backed forces continue their advance.
Sisi said on Saturday the Libyan cities of Sirte and Jufra, which the Tripoli-based Government of National Accord (GNA) is pushing to capture, are a red line for Egypt, warning the internationally recognized GNA not to cross the current front line with renegade military commander Khalifa Haftar's eastern-based self-styled Libyan National Army (LNA).
"If some people think that they can cross the Sirte-Jufra front line, this is a red line for us," he said before an audience that included some Libyan tribal leaders.
"If the Libyan people moved through you and asked us to intervene, this would be a signal to the world that Egypt and Libya are one country, one interest," he added.
During a tour of an airbase near Egypt's 1,200km-long (746 miles) western border with Libya, Sisi ordered his army to be ready to carry out any mission inside or outside the country to protect its national security amid tensions over Turkey's intervention in Libya.
"Be prepared to carry out any mission, here inside our borders - or if necessary, outside our borders," he told air force pilots and special forces personnel at the base, according to Al Jazeera.
He said the Egyptian army was "one of the strongest in the region", adding, "It is a rational army; an army that protects and does not threaten ... this is our strategy, our beliefs and our principles that we will never change."
Sisi's remarks a 'war declaration'
In reaction to the Egyptian president's comments, the Libyan army said Sisi's comments were "a clear declaration of war and a blatant interference" in Libyan affairs.
"[Abdel] al-Sisi's statements that Sirte and Jufra are a red line, according to his description, is a blatant interference in our country's affairs, and we consider it a clear declaration of a war on Libya," Abdel-Hadi Darah, a military spokesman of Path of Victory operation, said in a statement.
"Our heroic forces are determined to complete the journey and liberate the entire region from terrorist militias [loyal to warlord Khalifa Haftar], their mercenaries as well as their supporters," he added.
A member of the Tripoli-based government's presidential council also warned against Egypt threat of military intervention.
"We strongly reject what was said by Sisi and consider it a continuation of the war on the Libyan people, interference in Libyan affairs and a dangerous threat to national security," Mohammed Amari Zayed said on Saturday.
Earlier, Turkey had urged that forces loyal to General Haftar pull out of the strategic city of Sirte for a lasting ceasefire.
Presidential Spokesman Ibrahim Kalin made the remarks on Saturday, reiterating that Ankara fully supports Libya’s UN-backed government and that Sirte and al-Jufra should be cleared of the presence of Haftar’s forces for a “sustainable ceasefire.”
Turkey supports the GNA, which, with Turkish support, has reversed a 14-month assault on the capital by the LNA.
The LNA is backed by Russia, the United Arab Emirates and Egypt.