Egypt's parliament on Monday approved the deployment of armed forces abroad to fight "criminal militias" and "foreign terrorist groups" on a "western front", after President Abdel-Fattah al-Sisi said Cairo could intervene in Libya, reported Reuters.
The Egyptian parliament said in a statement that the troops would be defending national security, without giving further details or naming Libya directly.
The decision came after Sisi said last week that Egypt would not stand idle if there was threat to national security in Egypt and its western neighbour, Libya, if parliament gave its approval.
Shortly beforehand the Egyptian presidency said Sisi had agreed with US President Donald Trump to maintain a ceasefire in Libya and avoid any escalation.
Egypt is concerned about instability in Libya and Turkey's support for the internationally recognised government in Tripoli, whose fighters have moved closer to the central city of Sirte in the hope of recapturing it from the eastern-based Libyan National Army (LNA) of Khalifa Haftar.
Sirte is the gateway to oil-exporting ports which are held by the LNA and Sisi last month declared the Sirte front line a red line for Egypt, which supports Haftar alongside the United Arab Emirates and Russia.
Turkish support for the Tripoli government's forces helped force the LNA to abandon its 14-month offensive on Tripoli, a setback for Haftar's plan to unify Libya by force.
Sisi said last week Egypt would not ignore what he called threats to Egyptian and Libyan security. He said intervention in Libya would require the approval of parliament, which is dominated by his supporters.
A big escalation in Libya could risk igniting a direct conflict among the foreign powers that have poured in weapons and fighters in violation of an arms embargo.