Eight U.S. senators called earlier on May 17 for an independent federal investigation of whether oil giant BP violated civil or criminal laws in connection with the Gulf of Mexico oil spill.

It hasn't been determined when Obama will make the announcement of the presidential commission or when he'll sign the executive order, said the official, who did not want to speak on the record ahead of an announcement.

"The commission will take into account the investigations under way concerning the causes of the spill and explore a range of issues," the official said. In particular, the commission's inquiry will focus on industry practices, rig safety, regulatory regimes, federal governmental oversight -- including the structure and functions of the Minerals Management Service -- and environmental review and other protections, the official said.

Last week, Obama harshly criticized the companies involved in the spill, which threatens to become one of the nation's worst environmental disasters, and pledged to break up what he called the cozy relationship between regulators and the oil industry.

In testimony on Capitol Hill, BP touted its progress toward plugging the spill, but a top Obama administration official said the disaster is far from over.