President Barack Obama said on Saturday that offshore oil drilling could only go forward if there were assurances that a disaster like the massive Gulf of Mexico oil spill would not happen again.

As Obama officially unveiled a commission to investigate the accident, he issued a stern message that while keeping pressure on firms involved in the still-uncapped spill — BP, Halliburton and Transocean Ltd — he would also hold Washington accountable for mending its ways.

In his executive order announcing former Democratic Senator Bob Graham and former Environmental Protection Agency chief William Reilly would co-chair the panel, Obama also made his first reference to the possibility of a separate criminal probe into disaster.