A failed missile strike on Saudi Arabia's capital city has stressed tensions between the kingdom and Iran. Yemen's insurgent Houthi government said it launched a ballistic missile at Riyadh, which was shot down by Saudi forces before reaching the city's international airport. 

The Saudi government called the move an "act of war" and pointed a finger at Iran. The royal family has long blamed Iran for backing its fellow Shiite Muslims in Yemen and said this missile was the work of Tehran. Following the failed attack, Saudi-led forces bombed Yemen's capital, Sanaa. 

Shiite Houthi rebels took control of the majority-Sunni Yemen in 2015. Saudi Arabia is leading a coalition of Arab and Western powers against the insurgents.  Tehran denied accusations it was behind the attack. Iran and Saudi Arabia have been engaged in proxy wars in Yemen and Syria. The two nations are also vying for political soft power in Qatar, Iraq and Lebanon. 

Crown Prince Mohammed bin Salman, son of King Salman, has stepped up Saudi's efforts against Iran's influence in the Arab world after being named the next in the Saudi line of succession. Lebanon Prime Minister Saad al-Hariri resigned this weekend during a trip to Saudi Arabia, a move increasingly seen as having been orchestrated by the Saudi government. Hariri was locked in a power struggle between his Sunni coalition and Hezbollah, a Shiite political party and paramilitary force that shares governing power in Lebanon. Hariri claimed Iran was interfering with Arab states with the help of Hezbollah. 

A Saudi official said the kingdom reserved the right to respond to aggressions with force but didn't specify what measures — if any — would be taken against Iran. Iran is supplying Houthi militia with arms to attack Saudi Arabia and the UAE, Col. Turki Al-Maliki, spokesman for the Saudi-led coalition in Yemen, said on Sunday.

Al-Maliki also said the coalition would pay a financial reward for information about 40 Houthis wanted for terrorist crimes. Coalition forces have enough evidence to prove the full complicity of the Tehran regime in the Yemen conflict, Al-Maliki said.

At a presentation in Riyadh, he displayed missiles, weapons and military equipment supplied by Iran and seized by coalition forces. He said ballistic missiles used by the Houthis were not from the Yemeni Army arsenal, and came from Iran.

Iran also supplied the Houthis with drones, he said. Dismantled missiles and other arms were smuggled through Al-Hodeidah port in Yemen and assembled inside the country. The Houthis also threatened maritime navigation by using booby-trapped boats, he said.

Al-Maliki said the coalition had stepped up operations after Saturday night’s ballistic missile attack on Riyadh, but would not confirm air strikes on military targets in the capital, Sanaa, and elsewhere in Yemen after they attack.

Saudi defense forces intercepted and shot down the Houthi missile over King Khaled International Airport. Some debris landed in an uninhabited area but there were no casualties and the airport continued operating as normal.

Al-Maliki said the Houthis had launched the missile indiscriminately to target civilians in populated areas, which was a provocative act. Coalition forces would do whatever was possible to deter the threat from militants in Yemen, he said.

The Houthis have launched 78 missiles at Saudi Arabia, including one in July aimed at Makkah, since the coalition began fighting to restore the legitimate government in Yemen in March 2015