Egypt's top security body on Sunday pledged “all necessary and possible forms of support” to Saudi Arabia.
It met hours before parliament convened to vote on authorising President Abdel Fattah El Sisi to help defend the kingdom against attacks by the Houthi rebels in Yemen.
The National Defence Council, chaired by Mr El Sisi at Al Ittihadiya Palace in Cairo, said Saudi Arabia's security was inextricably linked to Egypt's own and to wider Arab national security.
The support would help the kingdom defend its security and territory, as well as the Islamic holy sites, the presidency said.
It cited the “escalating unacceptable attacks” on the kingdom and called for more diplomacy to calm the region.
The statement did not mention troops. But Mostafa Bakry, an MP and TV host close to the state, said on X that the council had approved sending forces to Saudi Arabia on “a defensive mission”.
The Prime Minister Mostafa Madbouly, Speaker of Parliament Hisham Badawy, Defence Minister Lt Gen Ashraf Zaher and intelligence chiefs attended.
Under Article 152 of Egypt's constitution, the President cannot declare war or send the army on a combat mission abroad without consulting the council. He also needs the approval of two-thirds of MPs. Parliament's rules require the vote to take place in an urgent closed session.
The emergency sitting was set for 1pm on Sunday. The House has a majority of pro-Sisi legislators who are widely expected to approve the request, as they have backed previous policies championed by the President.
Mr El Sisi made the request on Saturday.
“It is inconceivable that we would allow Saudi Arabia, its security or stability to be harmed,” he said. Egypt would act only if Riyadh asked, he said in a speech at the Military Academy. “We do not want to fight or attack anyone. We will only defend Saudi Arabia,” he added.
The move drew a swift warning from Sanaa. Yahya Al Raei, speaker of the Houthi-run parliament there, wrote to Mr Badawi on Saturday.
The Houthi-controlled body is not recognised internationally.
“We categorically reject Egypt being dragged” into “the same trench as the takfiri forces and the Israeli occupation entity,” he wrote. Such a path “would pose a grave danger to its national security,” he said, urging Cairo to take a “courageous stance”.
He accused Riyadh of waging “aggression and siege” against Yemen for more than 12 years. He said it had walked away from a peace road map and ended a period of calm by striking Sanaa airport. The letter was carried by the Houthis' Al Masirah TV.
Early on Sunday, the Saudi-led coalition said it had shot down two ballistic missiles fired at Khamis Mushait and three drones over Riyadh and the Eastern Province.
The Houthis have launched 20 attacks on Riyadh's King Khalid International Airport since October 1, coalition spokesman Maj Gen Turki Al Malki said on Thursday. Attacks on Saudi airports have killed 19 people and wounded 364, he said. The deadliest, on October 10 in Riyadh, killed 13, including an Egyptian flight attendant.
The coalition also said it intercepted a missile aimed at Madinah on Thursday. The Houthis denied firing it. The UN Security Council condemned the attacks as “escalatory” that same day and backed the kingdom's right to self-defence.
Cairo's move also comes as a new alliance takes shape around Riyadh. Saudi Arabia, Turkey and Pakistan signed the Makkah Joint Defence Agreement on August 7.
The pact provides that an attack on one member is treated as an attack on all. Riyadh activated it on October 5, and Pakistan said the partners would send the “agreed military forces” to the kingdom.
While Egypt is not yet a member, Foreign Minister Badr Abdelatty said last week that joining was “under serious consideration”.
Cairo has long been wary of binding pacts. Joining one could strain its ties with Iran and its peace treaty with Israel, while potentially drawing Egypt into a war with the Houthis.
Houthi attacks on Red Sea shipping have already caused heavy losses in Suez Canal revenue.
Over the past week, many commentators have cited Egypt's costly intervention in Yemen in the 1960s as a reason not to rush into such an agreement.
Instead, Cairo has taken smaller steps. On August 13, it joined a Saudi-led naval coalition set up after the Houthis declared a blockade on Saudi shipping.
Egypt joined the Saudi-led coalition that intervened in Yemen in 2015. In July 2020, MPs voted unanimously in a closed session to allow combat missions abroad as fighting in Libya neared Egypt's western border.
Approval of the request would not, in itself, mean that troops would be deployed.