By Toby Harnden in Washington
Published: 9:43PM BST 01 Jun 2010
The US president was speaking as Eric Holder, the United States Attorney General, visited the Gulf of Mexico coast to survey the damage and meet state attorneys general from Louisiana, Alabama and Mississippi.
Later Mr Holder said the US would launch civil and criminal investigations into the oil spill, saying they would "prosecute to the fullest extent of the law anyone who has violated the law... We will not rest until justice is done."
"We have an obligation to investigate what went wrong and to determine what reforms are needed so that we never have to experience a crisis like this again," said Mr Obama.
"If the laws on our books are insufficient to prevent such a spill, the laws must change. If oversight was inadequate to enforce these laws, oversight has to be reformed.
"If our laws were broken, leading to this death and destruction, my solemn pledge is that we will bring those responsible to justice on behalf of the victims of this catastrophe and the people of the Gulf region."
The very public consideration of criminal charges was the latest signal of a much harder line being taken by the Obama administration, which has publicly castigated BP in recent days for allegedly playing down estimates of the extent of the pollution of the Gulf, its beaches and natural habitats.
It will be Mr Holder's first trip to examine the damage and Obama administration sources said that a criminal investigation into the Deepwater Horizon rig explosion last month that killed 11 workers and its aftermath was virtually certain.
The Justice Department has already demanded that the companies involved in the spill, including BP, Transocean Ltd and Halliburton keep all documentation related to the accident because it could become part of an investigation.
Legal scholars have said the Justice Department was likely to consider potential violations of the Clean Water Act, the Endangered Species Act, the Migratory Bird Treaty Act and the Refuse Act.
Mr Obama, speaking after meeting the co-chairs of a new oil spill commission, also said if found guilty, BP would be held accountable for financial losses from what he called the "greatest environmental disaster of its kind in our history".
He said: "What is being threatened, what is being lost isn't just a source of income but a way of life".