U.S. officials say Secretary of State John Kerry will sign a landmark treaty regulating the multibillion-dollar global arms trade during the annual United Nations General Assembly meeting this week, the Associated Press reports.

The officials, speaking on condition of anonymity, said Kerry will sign the Arms Trade Treaty on Wednesday, Sept 25, initiating an uncertain ratification process in the U.S. Senate. Some lawmakers have expressed strong opposition to the United States becoming a party to the treaty.

The U.S. is the world's largest arms dealer and its accession is seen as critical to the treaty's success, although many of the world's other top arms exporters and importers have not signed the document.