Thursday's attacks in Istanbul - against the British consulate and the international bank, HSBC - came only five days after suicide attacks on synagogues in the city.
By Roger Hardy
BBC Middle East analyst
Diplomats and analysts have been quick to see the hand of al-Qaeda or one of its allies in the Istanbul explosions.
Al-Qaeda views the US and UK as one of a kind
Faced with this possibility, even probability, many Turks are at a loss to understand why they should have come under attack from fellow Muslims.
But in the minds of radical Muslims of the al-Qaeda type, modern Turkey has turned its back on the Muslim world and joined the West.
It is an ally of the United States and Israel, it is a member of Nato and a would-be member of the European Union.
And, crucially, it has been committed to secularism ever since it was founded as a modern republic in the 1920s.
So for Osama Bin Laden and those who think like him, it is not so much Turkey's policies they are fiercely opposed to; it is Turkey's world-view.
In this sense it is irrelevant whether the country does or does not send troops to Iraq.
Islamists loathe Turkey's secularism
It offered to do so, but withdrew the offer when it drew a hostile response from Iraqis.
It is irrelevant whether it is governed by a secular nationalist or, as at present, by a prime minister who calls himself a Muslim democrat (along the lines of Europe's Christian democrats).
Turkey has been targeted because, in the spectrum of Muslim thought, it represents the polar opposite of the "jihadi" Islam espoused by the radicals.
If Turks are asking why, so too are many in Britain.
The attackers seem to have deliberately targeted buildings with strong British connections - the British consulate and the London-based HSBC bank.
Britain, too, is a close ally of the United States.
Even as the bombers struck, the American president, George Bush, was on a state visit to London speaking warmly of his close friendship with the UK Prime Minister, Tony Blair.
Britain was singled out as a possible target in a statement sent to an Arabic newspaper in London after the attacks against two Istanbul synagogues on Saturday.
The statement, from a wing of al-Qaeda, said it had carried out the synagogue attacks - and warned that more "cars of death" would target America's allies, especially Britain, Italy, Australia and Japan.
If the string of attacks in Istanbul are indeed the work of al-Qaeda - working in tandem with local Islamic militants - it seems the group deliberately timed them to coincide with Ramadan, the Muslim month of fasting.
This year's Ramadan has already witnessed suicide attacks in Iraq and Saudi Arabia, as well as Turkey.
The holy month ends in a few days, and the bombers seem intent on bringing it to a close with a grim climax of violence.