Japan rejected a U.S. proposal on United Nations reform Friday despite receiving support for its quest to become a permanent member of the powerful U.N. Security Council.

Washington proposed Thursday expanding the number of permanent seats on the council from five to seven, with one for Japan.

The U.S. plan, however, would water down the agenda of the so-called Group of Four — Japan, Germany, India and Brazil — which wants six new permanent seats for a total of 11.