A missile attack this week on Riyadh has raised the risk of an escalation in the Yemen war in a region riven with interwoven conflicts between arch-foes Saudi Arabia and Iran.
The Saudi Minister for Foreign Affairs, Adel al-Jubeir, said on Tuesday that the Saudi Arabia has the right to respond to the Iranian threat.
Saudi Arabia sharpened its rhetoric against Tehran after Saudi forces shot down a flurry of missiles launched by the Iran-aligned Houthis on Saudi cities late on Sunday. One of the missiles caused the war's first casualties in the Saudi capital Riyadh when falling debris struck a home and killed an Egyptian man and injured two others.
Saudi King Salman, in comments carried by state media, pledged on Tuesday to "firmly and decisively thwart any hostile attempts" targeting the kingdom's security and stability.
A day earlier, the spokesman for the Saudi-led coalition fighting the Houthi movement accused it of using Iranian-made missiles and said that Saudi Arabia reserved the right to respond to Iran when and how it deemed appropriate.
"Iran is the appendicitis in the body of the world and should fix itself or else the world will fix the Iranian situation," spokesman Colonel Turki al-Malki said. Iran has repeatedly denied giving missiles to the Houthis.
Yemen's war fits into a broader decades-long struggle for supremacy between Middle East powerhouses Iran and Saudi Arabia, which fund and train proxy forces in Iraq, Syria and Lebanon and accuse each other of backing terrorism.
The war in the Arabian Peninsula's poorest country, which pits a coalition of Sunni Arab states friendly to the West against a Shiite armed movement sympathetic to Iran, has unleashed one of the world's worst humanitarian crises. The Houthis control the north of Yemen, including the capital Sanaa. Saudi Arabia and its allies have been fighting on behalf of an exiled government with a foothold in the south.
Saudi Arabia viewed the 2014 takeover of Sanaa by the Houthis as part of a regional strategy by arch-foe Tehran to encircle it. Independent U.N. experts reported to the Security Council in January that Houthi missiles they had examined and other military equipment had been manufactured in Iran.
The Houthis deny they are Iranian pawns, and say their spread throughout Yemen is a national revolution against corrupt government officials and Gulf Arab states in thrall of the West.
About 10,000 Yemenis have been killed and 53,000 wounded since the start of the coalition intervention in Yemen, which triggered what the United Nations has called the world's worst humanitarian crisis.
Around 22 million civilians, or 75 percent of Yemen's population, require humanitarian aid, according to latest U.N. data. The conflict has caused the worst cholera outbreak in modern history, with over 1 million reported cases.