What was not true about the korean war the soviets provided support to north korea north korea claimed sovereignty of the entire korean peninsula the war was at a stalemate by the end of 1951 the un supported a police action the peace treaty was signed in 1953

The incorrect item would be that a peace treaty was signed in 1953.  

No official peace treaty was ever signed at the conclusion of the Korean War. The agreement was only a cease-fire between military forces, not a treaty in which the governments agreed to terms with one another.

The Korean War occurred when communist forces from the North invaded the South in 1950, the United States intervened (with United Nations backing), battled to keep South Korea free and democratic, and were able to do so. The Korean War lasted from 1950 to 1953, and about 5 million people (soldiers and civilians) lost their lives in the conflict.  Korea remains divided at the same line where things stood prior to that war.