Turkey has decided not to send peacekeeping troops to Iraq, government officials have said.
There were angry protests in Turkey against a troop deployment
It follows fierce opposition from the US-appointed Iraqi Governing Council and public opinion in Turkey.
Last month, the Turkish parliament approved a deployment motion, after the United States, a fellow Nato member, requested more foreign troops.
The Turkish foreign ministry said Turkey would still play a key role in Iraq's post-war reconstruction.
A Turkish foreign ministry statement said Ankara made its decision after talks between Foreign Minister Abdullah Gul and US Secretary of State Colin Powell.
"We said from the beginning that we were not too eager anyway," said Mr Gul.
"We had said we would send if our contribution would be of use. We saw that this is not the situation. That's why we took this decision."
US State Department spokesman Richard Boucher said the decision had been taken in light of "Iraqi sensitivities".
Asked whether Washington totally ruled out a deployment of Turkish troops, he said: "Not forever - things may change".
"Circumstances may permit this at some point. But for the moment, it appears it's not going forward," he added.
The official Anatolia news agency said the Turkish military had stopped preparing for the deployment.
The BBC's Nick Thorpe in Istanbul says the deployment of Turkish troops was firmly opposed by the Iraqi Governing Council. It held that Turkey, as a neighbouring country, could not be trusted as a military player in Iraq.
He says fears were expressed that this might tempt other neighbours, like Iran and Syria to intervene.
The prospect of a 10,000-strong Turkish peacekeeping contingent was strongly opposed by Iraqi Kurds and Arab nationalists in Iraq, who recall Turkish rule under the Ottoman Empire as a time of repression.
Turkish troops retain a number of bases in northern Iraq, from where they have launched raids against Kurdish rebels regarded in Ankara as a destabilising influence on Turkey's Kurds.
The US had been hoping more countries would provide troops after a new UN resolution was passed last month, but Turkey was the only one to make a significant new offer, the BBC's Jon Leyne reports from Washington.