WASHINGTON (AP) _ International efforts have enabled the people of Kosovo to come a great distance since the end of the NATO air war against Yugoslavia, National Security Adviser Sandy Berger said today.

``All in all, we are on track in rebuilding the physical structure and in building political structures,'' Berger said. He spoke to a gathering at the U.S. Institute of Peace.

Although he was generally upbeat, Berger expressed outrage over the acts of retribution admitted by Kosovo Albanians against Serbs.

``NATO did not fight in Kosovo for one ethnic group over another,'' he said.

Since the end of the U.S.-led air war almost four months ago, Berger said, over 800,000 Kosovo Albanian refugees have returned to the province. Another 100,000 who were internally displaced have gone back to their homes.

The energy sector and hospitals and clinics have been revitalized and mail service has been resumed, Berger said. Childrenglg have been immunized and been able to return to school.

He said about 1.2 million square yards of Kosovo territory has been cleared of mines.

Although life is far from normal, Berger said, life is more normal than it was before the war.

``At last, children are learning in their own language,'' he said. ``What is occurring in Kosovo is ``the birth of something new. It is freedom.''