The US has vowed to hunt down the killers of at least 29 people, including eight Americans, who died in three explosions in the Saudi Arabia capital of Riyadh on Monday. Conor O'Clery, North America Editor. reports from New York.
The bombs have been blamed on al-Qaeda. "These despicable acts were committed by killers whose only faith is hate, and the United States will find the killers and they will learn the meaning of American justice," said the US President, Mr Bush.
Nine suicide bombers died in the three explosions, making this the most co-ordinated assault on US citizens since the September 11th, 2001, attacks on the World Trade Centre and the Pentagon.
Saudi authorities put the toll at 29 dead and 194 injured, with British, German, French, Australian, Filipinos and Arab citizens among the casualties.
The attackers drove cars packed with explosives at three foreign housing compounds late on Monday evening, detonating them and ripping the front off apartment blocks. A fourth blast at the headquarters of a joint Saudi-US company caused no casualties.
The FBI is sending investigators to help in the inquiry into the bombings, which occurred 13 days after the US State Department notified US citizens in Saudi Arabia that terrorist groups might be in the "final phases" of planning attacks.
In London, the Foreign Office last night warned of a "high threat" of more attacks against Western interests in Saudi Arabia, possibly with chemical or biological weapons.
The US Secretary of State, Mr Colin Powell, who was on a scheduled visit to Riyadh yesterday, said the strikes had "the earmarks of al-Qaeda".
"Terrorism strikes anywhere, everyone," he said on a tour of the devastated compounds. "It is a threat to the entire civilised world."
The attacks are a major embarrassment for US-ally Saudi Arabia. It is also a setback for the Bush administration's declared war on terrorism, and yesterday a number of Democrats criticised the Iraq war as a distraction from the goal of defeating al-Qaeda.
Speaking in Indiana, Mr Bush said: "The ruthless murder of American citizens and other citizens, reminds us that the war on terror continues...I figure we've destroyed about half of al-Qaeda. The other half is on the run...and we'll bring them to justice."
The UN secretary general, Mr Kofi Annan, said: "These acts must be totally condemned, and I hope this is a wake-up call for everyone that terrorism is not over yet and that we must all remain vigilant."
President Pervez Musharraf of Pakistan said he condemned "this heinous crime".
In a news conference broadcast live in the US, Crown Prince Abdullah said the "shameful attacks by criminal killers" would not disrupt the stability or security of Saudi Arabia.