FBI agents headed to Saudi Arabia today to join Saudi troops hunting for those who masterminded the triple suicide bombings that killed 34 people in the kingdom on Monday night.
Fifteen Saudis carried out the bombings against expatriate residential compounds, Saudi Foreign Minister PrinceSaud al-Faisal said.
Prince al-Faisal promised on US morning television to find those behind the attacks in Riyadh which killed at least seven Americans and has been blamed on al-Qaeda by the United States.
The blasts gutted housing complexes for foreigners in what was the first major attack on US targets since the United States waged war on Iraq.
"Whatever success they (al-Qaeda) think they have achieved they will be sorry for, because this country is now united against them in every way," Prince Saud said in an interview on NBC's "Today" show.
US President George W. Bush said the bombing meant the war on terror launched after September 11th, 2001, was far from over.
"We've destroyed about one half of al-Qaeda, the top operators of al-Qaeda, and that's good. But we've got more work to do," Mr Bush said.
An FBI spokesman in Washington said a team of agents had already left for Saudi Arabia. Saudi officials said the prime suspects in the blasts were a group of 19 al-Qaeda suspects, who disappeared in Riyadh last week after a shootout with police.
A high-level Saudi security official said the army was erecting checkpoints all over the vast desert kingdom.
"We believe this group is behind the terrorist attack and suspect that they have links to al Qaeda," he said.
Officials and terror experts said the attacks bore all the hallmarks of Saudi-born Osama bin Laden's al-Qaeda network, the group blamed for the 2001 attacks on America which prompted a US-led war on Afghanistan to try to root it out.The US State Department has recommended that US citizens currently in Saudi Arabia consider leaving the country. It also warned US citizens not to go to Saudi Arabia, citing increased security concerns because of the potential for further attacks. The new travel warning superseded a warning issued on May 1st in which Americans were strongly advised to avoid Saudi Arabia.
The earlier warning said US officials had information indicating that "terrorist groups may be in the final phases of planning attacks against US interests in Saudi Arabia."
The British embassy, which warned citizens to "maintain a high level of vigilance," but remained open, will hold meetings with members of the up to 30,000-strong community today.