Attorney General Eric H. Holder Jr. announced Tuesday that his office is using "the full weight" of its investigative power to pursue criminal and civil investigations into the oil spill that has devastated the Gulf Coast.

"The Department of Justice will ensure that the American people do not foot the bill for this disaster and that our laws are enforced to the fullest extent possible," he said.

Earlier in the day, President Obama vowed a "full and vigorous accounting" of the causes of the disaster, telling the leaders of a new commission that they should pursue the trail of blame without limits.

"They have my full support to follow the facts wherever they may lead, without fear or favor," Obama said in the Rose Garden on Tuesday after meeting with the co-chairmen of the commission, former Florida senator and governor Bob Graham and former EPA administrator William Reilly.

Holder's announcement came at an afternoon news conference in New Orleans, the same day the attorney general met with local law enforcement officials and surveyed part of the affected area.

"What we saw this morning was oil for miles and miles and miles, oil that we know has already affected plants and animal life along the coast and has impacted the lives and livelihoods of all too many in this region," he said. "This must not be forgotten."

Among the statutes his office is examining: the Clean Water Act, the Oil Pollution Act of 1990, the Migratory Bird Treaty Act and the Endangered Species Act.