Egypt's parliament convened on Sunday after President Abdel Fattah el-Sisi requested an emergency session to approve defensive military aid to Saudi Arabia, should Riyadh formally ask for support in its war with Yemen's Houthi movement.

El-Sisi declared on Saturday that Egypt will "carry out any measure to protect" Saudi Arabia, while expressing hope that parliament would grant him the necessary authorisation to proceed.

On Sunday, Egypt announced it would provide "all necessary and possible support to Saudi Arabia to defend its safety and stability." The National Defence Council, chaired by el-Sisi, said it "stands fully with" Saudi Arabia to defend its resources, territorial integrity and Islamic holy sites.

Under Egyptian law, the president cannot declare war or deploy the military on foreign missions without approval from parliament. For authorisation to be granted, at least two-thirds of members of the House of Representatives must vote in favour. The session was scheduled for 1pm local time (10am GMT).

Saudi Arabia has long been a strategic and economic partner of Egypt. El-Sisi stated last month that Saudi security is "integral" to Egypt's own security.

Political analyst and Gulf studies expert Thomas Bonnie James told sources that the Houthi threat to the kingdom is one of several "converging" pressures behind the decision. Economics is another key factor.

"Houthi pressure on [Bab] al-Mandeb threatens the Suez Canal, which Egypt's foreign minister says has lost about $11bn since the attacks began in 2023," James said, referring to Houthi strikes on Israeli-linked vessels passing through the strait, carried out in solidarity with Gaza.

James also noted that "millions of Egyptians live and work in Saudi Arabia, which is Egypt's largest single source of remittances. An Egyptian resident was killed, and others were injured in the attacks on Riyadh's airport."

He added that Egypt does not want to be seen as the regional ally that "stood aside while others defended the kingdom," noting that Turkey and Pakistan have already made their own pledges following the activation of the Mecca defence pact signed in August, amid deteriorating security conditions across the Middle East.

Hostilities in Yemen continue to escalate. Two air raids by the Saudi-led coalition struck Hodeidah in the southwest on Sunday. Saudi forces also intercepted drones near Riyadh and the Eastern provinces.

Riyadh's King Khalid International Airport has come under attack at least 20 times since fighting intensified between the internationally recognised government and the Houthis, also known as Ansar Allah.

Saudi-backed forces are fighting the Houthis on several fronts, including Taiz and Marib. Some analysts argue the Houthis are stretched thin following their summer gains, but James cautioned that "defeating them outright is a tall order."

"Ground forces backed by air power can retake the coastline; stopping missiles launched from the mountains is much harder," he said.

Egypt and Saudi Arabia have not signed a formal bilateral or multilateral defence cooperation pact. However, Cairo has a long history of cooperation with Riyadh. Egypt is a founding member of the Multinational Maritime Defense Coalition, which Saudi Arabia launched in July, aimed at protecting shipping in the Red Sea and through Bab al-Mandeb.

Houthis captured towns and cities near Bab al-Mandeb last month, though the internationally recognised government has since reclaimed some of those areas from the Iran-backed group.