President Barack Obama will address the American people from the Oval Office at 0000 GMT. The president's speech will focus mostly on the government's response to the massive oil spill in the Gulf of Mexico.
President Obama will speak after returning from his fourth trip to the Gulf region since the April 20 explosion and fire, which killed 11 workers and ruptured a deep-sea oil well.
The oil is starting to reach the Gulf beaches in Florida, and Mr. Obama told military personnel at the Naval Air Station in Pensacola, Florida, his administration is working hard to contain the damage.
"So, I want the people of this region to know that my administration is going to do whatever it takes, for as long as it takes, to deal with this disaster," said President Obama.
The president also emphasized that the White House will continue to hold the energy company BP responsible for paying the costs of dealing with the disaster.
"And that includes something else, making sure BP pays for the damages that it has caused," he added.
A White House spokesman says the president will talk to the nation about what his administration has done to help clean up the oil, limit the environmental damage and direct BP to stop the leak. He says Mr. Obama will also discuss efforts to minimize the economic impact on the people of the Gulf region, and to enact new safety regulations to prevent future disasters.
Meanwhile, on Capitol Hill, top executives of other major oil companies told lawmakers their companies would not have drilled the well the way BP did.
The leaders of ExxonMobil, Shell, ConocoPhillips and Chevron, as well as BP America, testified before a House of Representatives committee Tuesday.
The committee chairman, Representative Edward Markey, was among the lawmakers who rejected the argument, saying the other companies' emergency response plans are no better than BP's.
"The Gulf of Mexico response plans for ExxonMobil, Chevron, Conoco Phillips and Shell are virtually identical to BP's, and just as deficient," said Markey.
The president and chairman of BP America, Lamar McKay, again expressed his company's sorrow and regret for the incident, and promised that BP will pay for all damages related to the disaster.