By Timour Azhari and Tala Ramadan
RIYADH/DUBAI, Oct 9 (Reuters) - Thursday's attacks on Riyadh airport killed three people, Saudi authorities said on Friday, as Yemen's Houthi group stepped up missile strikes on the kingdom and tried to shut down its airspace in an escalating war triggered by the US-Iran conflict.
The strikes, which also injured several people, damaged a Saudia Airlines plane and sent smoke billowing over the airport, led many airlines to cancel flights to the Saudi capital days before
it is due to host a major meeting of global oil chiefs.
Saudi airstrikes hit Houthi targets in the Yemeni capital Sanaa overnight, Houthi officials and affiliated media said, part of an intensifying air war against the Iran-allied group aimed at reversing its recent territorial gains, threats to international shipping, and attacks on the kingdom.
A Saudi-led coalition backing government forces in Yemen said it had destroyed three missile launch platforms used by the Houthis and warned it would respond firmly to attacks on civilians.
The Houthis, who have encircled Yemeni government forces in Yemen's third-largest city of Taiz and are trying to defend positions on the Red Sea coast against a Saudi-backed offensive, had already killed three people with strikes on airports in the kingdom earlier this week.
The Saudi civil aviation authority said air traffic at Riyadh airport had returned to normal and flight tracking site flightradar24 showed a gradual resumption of flights, including from some Middle Eastern airlines.
Saudia Airlines said one of those killed on Thursday was one of its employees.
BITTER FIGHTING INSIDE YEMEN
Yemen's civil war has rapidly emerged as the fiercest front in a wider regional conflagration triggered by the US and Israeli attack on Iran that started on February 28.
The conflict is critical for global energy markets, with the Houthis firing on shipping in the Red Sea and its southern gateway the Bab el-Mandeb Strait, further squeezing Gulf oil supplies with Iran partly blocking the Strait of Hormuz.
Last month the Houthis staged a lightning advance down Yemen's Red Sea coast to take full control over the coastline around the strait, prompting Saudi Arabia to re-enter the long-dormant conflict and back a government counteroffensive.
On Monday government forces took back territory around the Bab el-Mandeb coastline after intense Saudi airstrikes and fighting continues there.
However, Houthi forces have also managed to cut off a key road connecting Taiz, a city of more than half a million people with a garrison of thousands of pro-government fighters, with advances in mountain districts.
The group has announced repeated rounds of ballistic missile fire at Saudi Arabia, proclaiming it would shut down Saudi airspace and warning workers at oil facilities that it would strike those too.
Saudi Arabia is seeking assistance from Pakistan and Turkey, its partners in a mutual defence pact, to help ward off Houthi attacks, and has pushed for wider help from allies to aid it in reversing the group's gains inside Yemen.
(Reporting by Timour Azhari in Riyadh and Tala Ramadan in Dubai; Writing by Angus McDowall; Editing by Toby Chopra)
