US President Barack Obama 'to extend oil drilling ban'
US President Barack Obama is set to extend a moratorium on deep-water offshore drilling for six months, the White House says.
The move comes as his administration faces criticism of its handling of the Gulf of Mexico oil spill.
The ban will stay in place while a commission further investigates the circumstances of the disaster.
BP says its latest effort to stem the flow of oil from the well after a rig explosion is going to plan.
Thousands of barrels of oil have been spewing into the Gulf at a depth of 1.6km (1 mile) every day since April's explosion on the Deepwater Horizon oil rig.
"[Mr Obama] will announce standards to strengthen oversight of the industry and enhance safety, a first step in a process that the independent Presidential Commission will continue," a White House aide was quoted as saying by Reuters.
"While the commission performs its work to determine how to prevent this from ever happening again, the moratorium on permits to drill new deep-water wells will continue for a period of six months."
President Obama is also expected to announce delays in exploration and drilling off the coasts of Alaska, and the cancellation of leases off the coast of Virginia.
He is due to visit the Gulf of Mexico for a second time on Friday. On Wednesday Mr Obama said the "heartbreaking" oil spill underscored the need to find alternative energy sources.
Tighter safety standards are also set to be recommended following the release of a preliminary report from the US Department of the Interior on lessons to be learned from the oil spill.
BP is attempting a "top kill" procedure to stem the flow of oil, which involves pumping mud into the breached well.
The US government has backed the procedure, which has never been tried at such a depth.
BP is under intense pressure to succeed after previous attempts to stem the leak failed.
A BP official said he believed mud, not oil, was exiting the well's ruptured pipe six hours after the work began.
"What you've been observing coming out of the top of that riser is most likely mud," said BP Chief Operating Officer Doug Suttles.
Company officials say it could be a couple of days before they know whether the "top kill" operation has worked.
BP Chief Executive Tony Hayward has put the operation's chance of success at 60-70%.
London-based BP has acknowledged a series of failures occurred on the Deepwater Horizon in the hours before the explosion that killed 11 workers and triggered the spill that has so far spewed at least 7 million gallons (26.5 million litres) into the Gulf.
Questions have been raised about whether proper procedures were followed on the rig.
On Thursday, US lawmakers will grill a number of officials on issues ranging from the environmental damage from the spill, the response of the administration and the impact on local businesses.
"You look at these thousands of gallons coming out - what can you say - it hurts," said Jarvis Davis, who runs a New Orleans seafood restaurant.
"They say they are going to help and cap things but they are destroying everything and they are not doing anything for us," Mr Davis told the BBC.
The spill is threatening a delicate coastal ecosystem and wildlife in the Gulf of Mexico, much of which was recovering from the effects of Hurricane Katrina which devastated the region in 2005.