The blast destroyed apartments and villas
The United States is sending federal agents to Saudi Arabia to help investigate the bombings that killed at least 34 people in the capital, Riyadh, on Monday.
President George Bush blamed Osama Bin Laden's al-Qaeda network for the attacks at three residential complexes for Western employees - and promised to hunt down those responsible.
However the president is facing criticism at home for focusing too much on Iraq, rather than al-Qaeda.
Meanwhile, updated figures from the official Saudi news agency added five more deaths to the previous toll of 29, without immediate explanation of the increase.
Riyadh bomb victims
Source: Saudi Interior Ministry
The latest deaths are believed to comprise one Briton, one Irish national, an Australian of Lebanese origin, a Filipino and one unidentified person.
Saudi Arabia's Crown Prince Abdullah, for his part, said the attacks had been carried out by "criminal butchers" who would be punished in hell for their actions.
The victims include 11 Westerners - mainly Americans - seven Saudis and several Jordanians, as well as nine suspected attackers, who shot their way past armed guards and rammed vehicles packed with explosives into the compounds.
The British Ambassador to Saudi Arabia, Sir Derek Plumbly, said two Britons were unaccounted for, although it was not clear whether one of these was the man reported dead.
Washington has told all non-essential diplomats and their family members to return home.
Investigators from the US Federal Bureau of Investigation (FBI) have been sent to Saudi Arabia, where they will gather evidence alongside Saudi police.
The FBI team includes a dozen agents, led by a senior official from the counterterrorism division.
Analysts say Saudi officials have been eager to rebut criticism by some US officials that they have allowed al-Qaeda operatives to operate.
More than 300 suspected militants have been arrested in Saudi Arabia since the 11 September attacks, Saudi officials say.
Saudi Arabia is the birthplace of Osama Bin Laden - who has repeatedly demanded that US forces leave the kingdom.
Fifteen of the 19 men suspected of carrying out the 11 September suicide attacks on New York and Washington in 2001 were Saudis.
As President Bush denounced the bomb attacks as "despicable acts" and vowed to bring those responsible to justice, he was himself criticised by a democratic rival.
Senator Bob Graham - who is seeking his party's nomination for next year's presidential election - said the bombings could have been avoided if the president had concentrated on fighting al-Qaeda rather than Saddam Hussein.
"The war on Iraq was a distraction," he said on Tuesday.
"It took us off the war on terror which we were on a path to win, but we have now let us slip away from us."
Other members of the US Congress accused the Saudi authorities of not doing enough to fight terror.
Tom Lantos, a Democratic congressman, said Saudi Arabia continued to protect militants.
However Crown Prince Abdullah, the country's de facto ruler, said his government was ready and willing to fight al-Qaeda.
"We promise that the nation is capable... of putting an end to this corrupt band and its supporters so severely that they will not be able to rise again," he said.
The prince said those who carried out Monday's attacks were "criminal butchers, devoid of any Islamic or human values" and "beasts, seeking only to shed blood".
"There is no other interpretation: These killers are cursed here on Earth, and in the hereafter their fate is hellfire," he said, quoting the Koran.
"If those murderers believe that their bloody crimes will shake even one hair on the body of this nation and its unity, they are deceiving themselves. If they believe they will shake the security and stability of our country, they are dreaming," he added.
The blasts in the east of the city also injured about 200 people.
Britain said it was tightening its port security in the wake of the attacks.
Customs officials said screening machines were to be installed at a number of British ports to stop "dirty bombs" - conventional bombs used to scatter radioactive material - being smuggled through by terrorists.