Saudi authorities on Friday said they had arrested a suspect in connection with a shooting attack on a police patrol in the mainly Shiite-populated eastern province of Qatif.
Three policemen were wounded in Thursday's attack in the town of Al-Awamiya, the state news agency SPA reported.
The suspect is on a list of people wanted by the authorities for disturbances in the Qatif region, an interior ministry spokesman said in remarks carried by the SPA on Friday.
"An initial investigation into the shooting of a security patrol in Al-Awamiya after dusk on Thursday confirms the implication of Mohammed Saleh Abdullah al-Zanadi," the spokesman said.
He said that Zanadi was "number 17" on the list of wanted people.
Zanadi was arrested after being hospital by relatives to be treated for gunshot wounds sustained in an exchange of fire with the police patrol, the spokesman added.
"The authorities will not be lenient in their efforts to arrest those wanted, and will deal with them in accordance with laws and regulations," the spokesman said, urging others on the list to surrender.
In January, the authorities published a list of 23 men wanted on suspicion of involvement in disturbances in the Qatif region, where seven people have been killed since November 2011.
At the end of February a Saudi interior ministry official described as "new terrorism" trouble that had erupted in Qatif, and said the authorities would "confront it the same way they did" with Al-Qaeda.
The official said those behind the incidents are a "minority that is being manipulated from abroad" -- an apparent reference to Iran.
Al-Awamiya has witnessed several demonstrations initially triggered by a Saudi-led military intervention in neighbouring Bahrain to help its Sunni rulers crush Shiite-led pro-democracy protests in March last year.
Later protesters took to the streets calling for reform in the ultra-conservative Sunni Muslim kingdom, according to activists.
Most of Saudi Arabia's estimated two million Shiites live in Qatif province, where the vast majority of the OPEC kingpin's huge oil reserves lie. Saudi Shiites complain of marginalisation in the kingdom.