The attacks themselves are no surprise; international observers had been expecting an Islamist backlash after the American-led invasion and occupation of Iraq. But the ferocity and frequency has been shocking. And yesterday there were still more.
The wave of suicide attacks in an arc that stretches from Morocco and Algeria through Israel where seven were killed yesterday to Saudi Arabia, Chechnya and Pakistan have been mounted by different violent groups for different reasons. Yet they stand as testimony to the inaccuracy of President George Bush's view that America is winning the "war on terror". They also fortify the position of those who say the war in Iraq was not so much part of that war as a diversion from it and that it has fuelled anti-Western attacks rather than reduced them.
And despite the arrest of four men in Saudi Arabia yesterday, the authorities in Riyadh admit that the masterminds of last Monday's bomb attacks are still on the loose.
Only days ago, Mr Bush declared that "al-Qa'ida is on the run" and that "about half of all the top al-Qa'ida operatives are either jailed or dead". In either case, he said, "they are not a problem any more".
Yet they are a problem. Some of their elements may have been badly dented by the US campaign against them, notably in Afghanistan. But last week's calculated and carefully planned anti-Western attacks, coupled with a new alleged tape from Osama bin Laden, have proved that they are still in business, and that significant numbers of their operatives are willing to destroy themselves in the name of their beliefs.
Some Democrats in the US are now taking up the issue in a surprisingly bold manner, given the huge support that Americans gave Mr Bush during the war on Iraq. They are asking: why did America go to war against Iraq when the war on al-Qa'ida was clearly of more importance?
The presidential candidate Senator Bob Graham of Florida spelt it out this weekend: "What this administration has done is they have conducted an ideological war in Iraq where they have not found the weapons of mass destruction upon which it was predicated and at the same time they have stopped the war against terror. We have let al-Qa'ida off the hook.''
Suicide bombers were in action again yesterday. This time it was an attack by Hamas, the most militant of the Palestinian nationalist-Islamist groups.
It came in response to the latest attempted negotiations between the Israeli Prime Minister, Ariel Sharon, and the new Palestinian Prime Minister, Mahmoud Abbas, over the doomed "road-map" and after yet another rash of Palestinian deaths at the hands of Israeli forces.
This was nothing to do with al-Qa'ida, nor was it about Iraq. But the rising temperature in the occupied territories cannot be excluded from the broader picture, not least because the US and British occupation of Iraq is certain to have deepened the conviction among fanatical Islamist anti-American militant groups of their own righteousness.
The sequence of yesterday's events was as familiar as it was revolting: disguised as an Orthodox Jew, a suicide bomber boarded a bus in central Jerusalem as the morning rush hour was getting under way. Seven passengers were killed. A second bomber blew himself up on the city's outskirts.
Israel imposed a "general closure" on the West Bank last night. The Israeli army said "Palestinians will not be allowed to exit and enter the territory of the state of Israel".
Hours before the attacks, talks between Mr Sharon and Mr Abbas the first between Israeli and Palestinian leaders in three years had ended. It was another addition to the list of problems confronting Mr Bush and his policy makers.
This list is lengthening. The aftermath of the war in Iraq has proved much harder than they expected. US efforts to turn the interim administration in Afghanistan into a national government with functioning security forces appear to be stalled, having been undermined by guerrilla attacks.
Saudi Arabia's arrests of suspects in the Riyadh suicide attacks a week ago was followed by the embarrassing admission that an earlier botched raid in which 19 suspects escaped was linked to the Riyadh bombing.
In Morocco, several dozen militants allegedly linked to the Casablanca bombings were said to have been detained. But the outlook is bleak, and likely to worsen.
Before the war on Iraq the Egyptian President, Hosni Mubarak, predicted that it would encourage global terrorism. "If there is one Bin Laden now," he said, "there will be 100 Bin Ladens afterwards."
Those words will have been ringing in the ears of the US Secretary of State, Colin Powell, who landed in Saudi Arabia hours before the bombings and toured the devastated site of one of the attacks.
By the time he had flown on to Moscow to meet the Russian President, Vladimir Putin, the second of two devastating suicide bombings in the Russian republic of Chechnya had taken place. Wednesday's attack by a female suicide bomber added 17 victims to the 60 people who died when a truck bomb exploded in the north of the country on Monday.
Even before Mr Powell's round of diplomacy aimed at getting a United Nations figleaf of support for the occupation of Iraq had ended, the bombers had attacked in Morocco.Reuse content