A Canadian citizen was in stable condition at a Saudi Arabian hospital on Saturday after being attacked in a shopping mall in the country's east, police said.
The attack came one week after a Danish citizen was shot and wounded in the kingdom's capital, a rare incident which has not been explained.
Police in Eastern Province said the Canadian was attacked with "a sharp object" while he shopped at a mall in the Gulf coast community of Dhahran.
"The authorities immediately rushed to the scene and arrested the perpetrator, a Saudi national," police said, according to the official Saudi Press Agency.
The victim was in "stable" condition, it added, without giving a motive for the attack.
On November 22, the Dane was shot in the shoulder "from an unknown source" as he drove away from his workplace in Riyadh, SPA said at the time.
The previous month, a Saudi-American former employee of a US defence contractor shot dead one American colleague and wounded another in Riyadh.
The suspect had recently been fired from his job, officials said.
That was the first deadly attack on Westerners in Saudi Arabia since several were killed in a wave of Al-Qaeda violence between 2003 and 2006.
Since September, Saudi Arabia, the United Arab Emirates, Jordan and Bahrain have participated in a US-led campaign of air strikes against the Islamic State (IS) extremist group in Syria, raising concerns about possible retaliation in the kingdom.
Canada and Denmark are among the countries -- with Australia, Belgium, Britain, France and the Netherlands -- participating in a similar campaign against IS in Iraq.