WASHINGTON (AP) — With the scrapping of a landmark arms control agreement Friday, the U.S. announced plans to test a new missile amid growing concerns about emerging threats and new weapons.

U.S. officials said they are no longer hamstrung and could now develop weapons systems previously banned under the Intermediate-range Nuclear Forces treaty with Russia, a Cold War-era agreement that both sides repeatedly accused the other of violating. The treaty was also criticized because it did not cover China or missile technology that did not exist a generation ago.

The end of the treaty comes amid ri...