The Iran-backed Houthi movement says it has attacked Abha International Airport, King Khalid Air Base and facilities belonging to state-owned oil giant Aramco in Abha and Jizan in Saudi Arabia.
According to Saudi authorities, the attacks have led to fires and temporary shutdowns. Yemen's Saudi-backed central government has announced that its forces will respond to the Houthis' "dangerous escalation."
International reactions
Both the UN chief and the EU condemn the attacks:
The attacks violate international law, undermine regional security and stability, and risk further jeopardizing efforts to reach a peaceful solution to the conflict in Yemen, said Anouar El Anouni, spokesperson for the EU on foreign affairs.
"We naturally express deep concern about the reports of civilian casualties," said UN Secretary-General António Guterres.
Later on Tuesday, Houthi-controlled news sources reported that Saudi Arabia had attacked targets in Taiz province, where fighting has been ongoing for several days. Saudi attacks were also reported from Marib province.
Death toll rises
Around 500 people have been killed in fighting between the Houthi movement and Yemeni government forces since Thursday, when the Houthis launched an offensive targeting the government-controlled port city of Mocha.
The Houthis are also trying to advance in the Bab al-Mandab Strait, the southern gateway to the Red Sea.
The waterway has become increasingly important since traffic in the Strait of Hormuz was blocked due to the Iran war.
The UN migration agency IOM says that over 18,500 people in Yemen have been forced to flee as a result of escalating fighting in recent days. Hundreds are reported to have been killed in the fighting.
