U.S. NATO ambassador says Afghan policy intact CHICAGO (Reuters) - The U.S. ambassador to NATO said on Thursday the alliance is committed to its policy in Afghanistan despite recent attacks on military advisers and U.S. soldiers in a violent outcry against the burning of copies of the Koran at a NATO military base. "What happened in the last few days are the kinds of thing which we condemn, that are unacceptable," Ivo Daalder told reporters after a speech to the Chicago Council on Global Affairs. But we can't have a few situations, which are tragic, ... be the determining factor in our policy. We think we have the right policy. We're determined to see it through," he said. Speaking in Chicago where NATO will hold its annual summit on May 21, Daalder said leaders of the 28-member alliance will discuss the next phase of the transition to Afghan-led security. Western officials have been hoping the violent outcry that erupted last week in Afghanistan following the burning of copies of the Koran at a NATO military base will soon pass, allowing them to focus on the other major challenges that remain before most foreign combat troops are due to leave Afghanistan at the end of 2014. The killing of the U.S. officers in the Interior Ministry on Saturday stunned NATO and cast doubt on its strategy of replacing large combat units with advisers as the alliance tries to wind down the war, now in its 11th year. NATO immediately moved to withdraw all its advisers from Afghan ministries in Kabul. Britain, Germany and Canada then withdrew their advisers. Some NATO staff have been allowed to go back to the ministries. Separately, Daalder was asked about what NATO uses as criteria for intervening militarily, such as in Libya last year and why it is not doing so now in violence-torn Syria. Daalder said there were three conditions, and Syria certainly met the first one of a humanitarian need but offered that there was neither regional support nor a legal basis for intervening. He cited Russia and China blocking United Nations Security Council resolutions on Syria. "Frankly, I doubt we'd get to the point that we'd have that basis (to intervene in Syria)," he said. Another topic to be discussed at the upcoming NATO summit will be the capability and deployment of a missile defense system to guard Europe from a growing ballistic missile threat, Daalder said, citing an unspecified threat from the Middle East that many in the audience understood referred to Iran. Russia has protested NATO's plan to position missile interceptors in Romania and Poland, but Daalder said there were ongoing discussions to try to allay those concerns. " (The missile defense system) will be decided upon and implemented not in order to threaten Russia but in order to strengthen the security of Europe," he said, calling Russia an ally and friend with whom one sometimes disagrees. Reporting By Andrew Stern; Editing by Eric Walsh