Section 3 of the AECA defines violations: http://www.pmddtc.state.gov/regulations_laws/aeca.html
Section 3(c)(2) requires that we promptly report when a "substantial violation" of any agreement under which the U.S. provides defense articles under the FMS program "may have occurred." The agreements under which we make FMS sales require in relevant part that recipients use the items only for internal security or legitimate self-defense. Whether a violation is "substantial" is determined by reference to the quantity of items involved or the gravity of the consequences. A report would not make a country ineligible for further security assistance unless the President so determines and reports to Congress, or Congress enacts specific legislation.
Section 3(e) further states:
If the President receives any information that a transfer of any defense article, or related training or other defense service, has been made without his consent as required under this section or under § 505 of the Foreign Assistance Act of 1961, as amended, he shall report such information immediately to the Speaker of the House of Representatives and the Committee on Foreign Relations of the Senate.