SpaceX said Thursday it “forcefully rejects” the Federal Aviation Administration’s contention it failed to follow license requirements and did not get approval for changes before two launches in 2023.

The FAA this week proposed to fine SpaceX $633,000 over the alleged violations.

SpaceX said in a letter to Congress released Thursday that the FAA was failing to “keep pace with the commercial spaceflight industry” and suggested the fine may be tied to increased scrutiny from Congress of the FAA space oversight. SpaceX added it has been clear for some time the FAA’s commercial space office “lacks the resources to timely review licensing materials, but also focuses its limited resources on areas unrelated to public safety.”