RIYADH: Riyadh's Kingdom Centre skyscraper ordered remote working for office tenants on Sunday following repeated Houthi attacks on Saudi Arabia.
The imposing, 99-storey landmark announced "mandatory" remote working until further notice.
No reason was given for the order, but it comes a week after 13 people were killed in a major Houthi attack on Riyadh's international airport.
The Saudi coalition's decade-plus war with the Iran-backed Houthis has reignited during the US-Iran war, with regular attacks reported by both sides.
Tenants of the Kingdom Centre, which towers over central Riyadh, include financial services giant Merril Lynch, management consultancy McKinsey and the International Monetary Fund.
"Please be advised that remote working arrangements are mandatory for all office employees at Kingdom Centre, effective immediately and until further notice," the building's management said in an email seen by AFP.
"Kindly refrain from attending the offices during this period," it added. The mall at the foot of the building remains open.
It comes as schools recently extended remote learning measures and Riyadh's airport remains closed after last week's attack.
The order came after the coalition announced the death of two helicopter pilots in Najran near the border with Yemen, blaming a "technical malfunction", after the Houthis said they shot down an Apache helicopter in the area.
Late on Saturday, Houthi spokesman Yahya Saree said the group had "downed an Apache helicopter belonging to the Saudi enemy" in the same area.
After an uneasy, four-year truce, Yemen's conflict has surged back to life and intensified when the group seized strategic territory along the Red Sea coast last month.
The Houthis have hit Saudi targets including tankers in the Red Sea, oil facilities and Riyadh's King Khalid International airport.
The Saudi-led coalition backing the internationally recognised government has launched repeated air raids on Houthi territory.
The coalition said overnight it intercepted two drones in the Riyadh area and a third over the oil-rich Eastern Province. Saudi authorities had earlier issued a threat alert in the capital.
The coalition also said two ballistic missiles were intercepted in the kingdom's south.
On Saturday, the Houthis reported that Saudi strikes killed 12 people in Yemen, including three children.
The Houthis have declared a maritime blockade on Saudi Arabia and captured territory around the Bab al-Mandab strait, the Red Sea chokepoint and vital export route for Saudi oil since Iran blockaded the Gulf's Strait of Hormuz.
The Red Sea is a key shipping route, connecting Asia with Europe via Egypt's Suez Canal.
On Sunday, Egypt's parliament will hold an emergency session after President Abdel Fattah al-Sisi asked lawmakers to authorise support to defend Saudi Arabia against Houthi attacks.
Sisi said he was willing to "carry out any measure to protect" Saudi Arabia if its leaders requested it.
"I'm not talking about fighting anyone or attacking anyone," he said on Saturday. "We are speaking only about defence."
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