"I ultimately take responsibility for solving this crisis," Obama said during a visit to Louisiana to inspect oil spill damage. "I am the president and the buck stops with me.

Public opinion has dimmed over Obama's handling of the crisis and his Gulf inspection interrupted a family vacation to check up on progress, including a stop at a local beach to witness oil tar balls washed up from the sea.

Defending his response, Obama said the government had begun gathering vessels and equipment to deal with the cleanup from the first days of the accident. He also stressed there were no simple solutions to the spill.

"There are going to be a lot of judgment calls involved here. There are not going be silver bullets or a lot of perfect answers for some of the challenges that we face."

BP earlier reported progress in its efforts to close off the gushing Gulf of Mexico well. But Obama emphasized that success was not guaranteed.

"Right now we are still within the window when we don't yet know the outcome of the highly complex 'top kill' procedure," he said after being briefed on progress to plug the well.

"Even if the leak was stopped today, it wouldn't change the fact that these waters still contain oil from what is now the largest spill in American history, and more of it will come ashore," he cautioned.