A Yemeni man was arrested after he stabbed three performers during a live play in Riyadh on Monday.
Saudi Police said the victims were in stable condition but offered no information about their nationality or the assailant's motives.
A police spokesman told the Saudi Press Agency that "security forces dealt with a ... stabbing attack against two men and a woman during a live performance".
State television footage showed the 33-year-old attacker climbing on to the stage in King Abdullah Park during a musical performance by what appeared to be a foreign troupe.
King Abdullah Park is one of the venues hosting the two-month Riyadh Season entertainment festival, part of a broad government push to open up the kingdom to tourists and diversify its economy away from oil.