MOSCOW — President Vladimir V. Putin on Thursday strongly defended Russia’s implacable opposition to military intervention in Syria and sharply chastised the United States for its role in toppling Col. Muammar el-Qaddafi of Libya, describing that outcome as a mistake that created chaos and ultimately led to the death of Ambassador J. Christopher Stevens in Benghazi.

However, speaking at his annual end-of-year news conference, he made clear that Russia, Syria’s longtime ally, was now mainly concerned about averting “never-ending civil war,” not preserving the rule of President Bashar al-Assad.

“We are not concerned with the fate of Assad’s regime,” he said. “Of course, changes are being demanded, but it’s something else that concerns — what will happen next?”

In recent days, the Kremlin has sounded increasingly pessimistic about Mr. Assad’s government, and Russian officials have acknowledged developing contingency plans to evacuate thousands of Russia citizens, mostly women wed to Syrians who had studied at Russian universities.