At least three people were killed and dozens injured in Houthi attacks on two international airports in Saudi Arabia, including one in the capital Riyadh.

Saudi Arabia's civil aviation authority said in a statement Wednesday that Abha International Airport and King Khalid International Airport were targeted in attacks on Tuesday and Wednesday.

An Egyptian and an Algerian national were killed at Abha airport, while a Sudanese national was killed at the airport in Riyadh, the authority said. A total of 36 people were wounded in the attacks.

The Houthis claimed responsibility for a series of attacks, including a ballistic missile strike targeting Riyadh's King Khalid International Airport.

The conflict is increasingly drawing in other regional powers.

Pakistan and Turkey agreed Tuesday to activate the Mecca Pact, a joint defence agreement they signed with Saudi Arabia in August.

Middle East Eye reported Tuesday that Turkey is sending troops and air defence systems to Saudi Arabia to protect the kingdom's infrastructure.

Pakistan also confirmed in an interview with CNN that it is deploying troops to Saudi Arabia under the pact.

At least 200,000 displaced

Saudi Arabia is also intensifying its strikes on Houthi-controlled areas in support of Yemen's internationally recognised government, as it seeks to reverse Houthi advances.

Heavy fighting is underway between the Saudi-backed Yemeni government forces and the Houthis along Yemen's Red Sea coastline and around the city of Taiz.

More than 200,000 people have already been displaced by the conflict, the United Nations said Wednesday.

Earlier this week, Yemen's internationally recognised government, backed by Saudi Arabia, launched a counteroffensive to retake Red Sea coastal areas seized by the Houthis last month.

The Yemeni government said Sunday that the broader objective of the campaign is to retake all territory it has lost to the Houthis during 12 years of war.

The front lines have shifted rapidly, while images of intense fighting have emerged on social media.

Several videos appeared to show fighters in an armoured vehicle from the Giants Brigade, which is aligned with Saudi Arabia and Yemen's government, firing on unarmed men and people who were surrendering on a beach.

Yemen's government said Tuesday that it had recaptured the Arabian Gulf side of the Bab el-Mandeb Strait and Mocha, the strategic Red Sea port city that the Houthis seized from government forces in September.

Houthi channels have denied that Mocha has been recaptured, posting videos purportedly showing their fighters inside the city.

Other reports and open-source information appeared to support the Houthi claim, indicating that fighting around the port city has largely involved long-range missile exchanges and that Mocha remains under Houthi control.