Washington is pushing Tokyo to pay an additional $1 billion over the transfer of U.S. Marines from Okinawa to Guam, reneging on an earlier pledge to shoulder the costs itself, sources close to bilateral relations said Saturday.

Specifically, Japan has been asked to cover the equivalent of ¥82 billion in extra costs to construct American military facilities on the U.S. territory, despite a bilateral agreement to share the financial burden, the sources said.

The request was initially made during a recent review of the realignment of American forces in Japan, and comes as the U.S. Congress cranks up the pressure on President Barack Obama to cut federal expenditures.