Three suspected members of the terror group al-Qaida managed to escape Sunday following a hostage standoff that began Saturday at the offices of the Al-Khobar Petroleum Center building, located about 400 kilometers northeast of the Saudi Arabian capital, Riyadh.

The standoff ended Sunday when Saudi commandos stormed the complex, but not before 22 civilians, most of them foreign, were killed and more than two dozen others were wounded.

A total of about 50 people were being held hostage and about 240 other people in the building were safely evacuated. Several state security officers were also believed killed during the attack.

Saudi authorities said the leader of the group, described as one of the kingdom's most wanted terrorists, was taken into custody. Three others managed to escape.

The siege began Saturday when gunmen wearing military clothes opened fire on the complex before storming the offices and employees homes.

An Internet statement purported to be from al-Qaida terrorists claimed responsibility for the attack and vowed to rid the kingdom of what it called infidels.

Earlier this month, a similar attack was carried out at an oil facility in the Red Sea town of Yanbu. And, according to a journalist with the Arab News in Jeddah, Mahmud Ahmed, Saudi citizens are becoming increasingly upset with acts of terror in the kingdom.

"Let me tell you, they are very angry. Extremely, extremely, extremely angry because, you know, Saudis are angry because Saudi Arabia is known to be a safe place," says Mr. Ahmed. "And now these terrorist operations are just scaring local Saudis, and they are very angry about it."