The treatment of Turkey's hopes of joining the EU is an "acid test" of tackling terrorists' attempts to sow division, Jack Straw has said.
Straw: "Western" values are universal
In a speech in Copenhagen the foreign secretary argued more had to be done to show that the Islamic world and Europe were not doomed to conflict.
Europe and the US must stress their values were universal and not "Western" or "Judaeo-Christian".
He said: "There is a real risk that we let the terrorists spread divisions."
He continued: "The crucial point which I want to make today is this: we must stay together in Europe, and internationally, to combat this common threat.
"And we must combat division by engaging with people of different faiths and origins on the basis of the universal values for which we all stand."
Values of tolerance and pluralism were not exclusive to Europe or the US, but featured in the aspirations of people around the world, he said.
Division could also be fought by promoting a better understanding of how much Europe shared with the Islamic world and by "active engagement", Mr Straw continued.
"For me, the acid test of this is the question of Turkey's candidacy of the EU," he said.
"If we believe, as I strongly do, that Europe's strength lies not in a Judaeo-Christian club but in a diversity of traditions underpinned by common and universal values, then we must fulfil our engagements to Turkey.
"We have recognised Turkey as a candidate for membership. Now we must be clear that Turkey will be treated as any other EU candidate, without fear or favour."
Mr Straw said he hoped that if Turkey met the necessary criteria, it could be given a commitment in December on opening talks over EU membership.
Turkey still had to make further progress before being ready to join the EU, he said, but it was committed to reform and modernisation.
Human rights had been identified as a key area where change is needed.
But there have been complaints inside Turkey that the EU is biased against the country because of its predominantly Muslim faith and its population of some 70 million, which would make it the second largest EU member after Germany.
Mr Straw also used his speech to reiterate that there could be "no opt-out" from the war against terrorism.
He argued that leaving Iraq or Afghanistan would not end the ambitions of "insatiable" terror groups like al-Qaeda.
The foreign secretary also underlined the need to work for progress on the "roadmap" for peace in the Middle East, where violence is expected to avenge the killing of Hamas founder Ahmed Yassin.
His speech comes after EU foreign ministers on Monday unveiled new measures to prevent terrorist attacks.
In a draft declaration after talks in Brussels, they urged EU states to mobilise all their resources, including military ones, to deal with the threat.
Some security experts believe British and American security services are not always willing to share their information with other nations.
Mr Straw told BBC Radio 4's World At One there was already good cooperation with other nations, although there was not the trust needed to share intelligence with some smaller nations with less developed security services.
Some EU states have still not introduced the anti-terror measures agreed after the 11 September attacks, such as a European arrest warrant.
The Madrid bombings had concentrated minds, said Mr Straw, and a deadline of 30 June was to be set for states to implement the measures.