TOKYO — The United States claimed two medals in boxing on the last day of the Olympics as the lightweight Keyshawn Davis and Richard Torrez Jr., a super heavyweight, both earned silver medals.

While the Americans have not secured a gold medal in boxing since the Athens Games in 2004, the two silver medals on Sunday, plus a silver won by Duke Ragan and a bronze collected by Oshae Jones earlier in the tournament, were an improvement for America’s boxing program: The four medals meant this was the most successful Olympic Games for the United States since 2000.