Security sources said on Thursday interrogation of the suspects revealed that six of them had ties with Abu Musab al-Zarqawi, head of the al-Qaida network in Iraq, while the others belonged to an underground Saudi group known as the Brigades of the Holy Shrines.

"They were planning attacks on foreign officers in the kingdom," said one security source, referring to a plot to attack US military personnel who frequent five-star hotels while on leave from duty in neighbouring Iraq.

The arrests came after an investigation that used informers to hunt Jordanian suspects allied to al-Zarqawi who help recruit people to fight against US troops.

"The interrogations revealed their membership of these underground groups. They were recruiting terrorists for al-Qaida in Iraq and collecting donations for the organisation," said another security source.

Jordanian intelligence has stepped up its vigilance after receiving warnings of possible attacks against Western targets in the kingdom after the latest bomb attacks in London and the Egyptian resort of Sharm al-Shaikh.

Prosecutors were expected to issue a formal indictment against the suspects, who will be charged with conspiracy to carry out terror attacks, which carries the death penalty.