"I think the Justice Department has been down in the Gulf to look at and to gather information on this," Gibbs said on CBS's "Face the Nation" when asked whether a criminal investigation may be opened.
He refused to elaborate on possible charges or say whether a federal investigation has been opened.
The first priority must be stopping the flow of oil into the gulf, he said.
"But I can assure you that the Department of Justice has been there, as every bit of government has been activated to try to plug this hole," Gibbs said.
The spokesman defended the Obama administration against claims from Republicans and some Democrats that it did not respond adequately to the explosion and subsequent leak.
"There's a lot of criticisms that one can have, certainly for BP and even for the government, in how we got to this," Gibbs said. "But I don't think anybody could credibly say -- even as frustrated as they are and as frustrated as we are -- that the government has stood around, done nothing and hoped for the best."
Gibbs noted the Coast Guard was on the scene moments after the rig exploded and said the U.S. government is "doing everything humanly and technologically possible to plug the hole 5,000 feet below the ocean and to do everything we can to contain (oil's) spread and to deal with its environmental and its economic impacts."
Ultimately, though, responsibility for capping the well lies with its owner, BP, Gibbs said.