Before entering into negotiations concerning any proposed foreign trade agreement under section 1351 of this title, the President shall furnish the United States International Trade Commission (hereinafter in sections 1352(a), (c), 1354, and 1360 to 1367 of this title, and section 624(b) of title 7, referred to as the “Commission”) with a list of all articles imported into the United States to be considered for possible modification of duties and other import restrictions, imposition of additional import restrictions, or continuance of existing customs or excise treatment. Upon receipt of such list the Commission shall make an investigation and report to the President the findings of the Commission with respect to each such article as to (1) the limit to which such modification, imposition, or continuance may be extended in order to carry out the purpose of said section without causing or threatening serious injury to the domestic industry producing like or directly competitive articles; and (2) if increases in duties or additional import restrictions are required to avoid serious injury to the domestic industry producing like or directly competitive articles the minimum increases in duties or additional import restrictions required. Such report shall be made by the Commission to the President not later than six months after the receipt of such list by the Commission. No such foreign trade agreement shall be entered into until the Commission has made its report to the President or until the expiration of the six-month period.