Ballistic missiles were intercepted on Saturday in the sky above Saudi Arabia's capital Riyadh and the southern city of Jizan, Reuters reported citing Saudi state media and the Saudi-led coalition fighting in Yemen.
Residents in Riyadh reported multiple blasts around 2320 (2020 GMT), followed by emergency vehicle sirens in some northern districts.
Saudi state news agency (SPA) claimed the missiles were launched by Yemen's Houthi militia.
Yemen's Houthis, battling the Saudi-led coalition, have launched hundreds of missiles and drones across the border, mostly at nearby military and civilian targets but also at Riyadh. The last attempted strike on the capital was in June 2018.
"Two civilians were slightly injured due to the falling of the intercepted missile's debris as it exploded in mid-air over residential districts" in Riyadh, SPA reported, citing a Saudi civil defence spokesman, Lt. Colonel Mohammed Al-Hammadi.
No fatalities had been recorded from the shrapnel that fell on Riyadh, in the centre of the kingdom, and the southwestern city of Jizan, located on the Red Sea directly north of the border with Yemen, SPA said, citing coalition spokesman Colonel Turki al-Malki.
The spokesman added that firing missiles at this time by the Houthis and Iranian Revolutionary Guards showed the real threat the group and Iranian regime supporting it pose, adding that this escalation does not reflect the group's announcement that it is welcoming a ceasefire.
Saudi Arabia blamed Iran for a September 2019 drone and missile attack on two oil installations that initially halved Saudi oil output, even after the Houthis claimed responsibility. Tehran denies involvement.
The Saudi-led coalition intervened in Yemen's civil war in 2015 to try to restore the internationally-recognised government of President Abd-Rabbu Mansour Hadi, ousted by the Houthis in 2014. Tens of thousands of people have died in the conflict that is widely seen as a proxy war between Saudi Arabia and Iran.