What was seen by U2 spy planes that caused the American military to become concerned?

United States and the Soviet Union that began with the shooting down of a U.S. U-2 reconnaissance plane over the Soviet Union and that caused the collapse of a summit conference in Paris between the United States, the Soviet Union, the United Kingdom, and France.

Explanation:

answer; i believe its a

as general terms,  indian territory,  the indian territories, or  indian country  describe an evolving land area set aside by the  united states government  for the relocation of  native americans  who held  aboriginal title  to their land. in general, the tribes ceded land they occupied in exchange for  land grants  in 1803. the concept of an indian territory was an outcome of the 18th- and 19th-century policy of  indian removal. after the  civil war(1861–1865), the policy of the government was one of  assimilation.