JEDDAH, 16 April — Deputy Interior Minister Prince Ahmad yesterday confirmed the arrest of Abdul Hamid Al-Mubarak, organizer of a pro-Palestinian demonstration in the eastern city of Dhahran.

“Yes, A-Mubarak has been detained because he is an instigator,” Prince Ahmad told Okaz daily.

The prince cast doubts on Mubarak’s mental health, saying family members had confirmed he has an “unstable” personality.

“Unfortunately, he is untrustworthy — although he is a university professor in the Eastern Province. If he had had any common sense, he would never have spoken to Al-Jazeera satellite channel, Prince Ahmad said.

Mubarak is head of the Popular Committee for the Support of Palestine, which called for the demonstration.

Security officers blocked the protest rally before it reached the US Consulate on April 5.

Prince Ahmad said that Mubarak, 47, “was still in custody so that procedures to take their normal course,” an indication that he will be tried in a court of law.

Mubarak, a professor of Islamic jurisprudence at King Faisal University in Ahsa, publicly called for the demonstration on Doha-based Al-Jazeera and spoke again to the television as security forces were dispersing participants.

He said “tens of thousands” of people had come to take part in the rally. But Prince Ahmad said only “150 to 200 people had participated in the protest”; the other people, according to him, were just onlookers.

Prince Sultan, second deputy premier and minister of defense and aviation, stated recently that such demonstrations and street protests will not serve the Palestinian cause.

Interior Minister Prince Naif urged Saudis to back the Palestinians with constructive action. Prince Naif told the “zealots” who took part in the demonstration to help the Palestinians by making donations.

In his interview with Okaz daily, Prince Ahmad said the government has taken steps to send urgent relief supplies to the Palestinians through the Saudi Red Crescent Society and international relief organizations.