Expanding offshore drilling is a deeply contentious issue
The US House of Representatives has approved legislation which would lift a 27-year-old moratorium on drilling for oil in US coastal waters.
Drilling would be allowed between 80km (50 miles) and 160km (100 miles) of the coast, but not inside that limit.
The House voted 236 to 189 in favour of the extensive energy package, which was drawn up by the Democrats, who had previously opposed coastal drilling.
Republicans denounced the bill as a political ruse.
President George W Bush lifted an executive ban on drilling for oil in most US coastal waters in July, urging lawmakers to follow suit in order to reduce US dependence on oil imports.
The move came as high oil prices pushed US petrol prices above $4 per gallon (Ł0.59, or 0.79 euro, a litre).
Democratic House Speaker Nancy Pelosi said the bill marked "a new direction in energy policy" because of its emphasis on alternative energy.
Until recently, Democratic leaders had opposed ending the drilling ban, pointing out that oil companies already have 68m acres under government leases they can drill.
Official estimates show that nearly 90% of the oil believed to lie off the US coast would remain off limits because it is located within 80km of the shore.
Petrol prices are part of the wider US energy policy debate
Republicans say the bill is a ruse to provide political cover for Democrats who have felt under pressure to show support for more drilling at a time of high oil and fuel prices.
A White House statement said "this bill purports to open access to American energy sources while in reality taking actions to stifle development".
The Senate will consider a similar bill later this week.
US energy needs are set to be a key issue in November's presidential election.
Republican John McCain is in favour of offshore oil drilling, whereas his Democratic rival, Barack Obama, opposes it.
Environmentalists say offshore drilling would take at least a decade to have any effect on oil supply and would exacerbate climate change.
Since 1981, a congressional moratorium has prohibited oil and gas drilling along the east and west coasts and in the eastern Gulf of Mexico, an area accounting for some 80% of the US's outer continental shelf.
The executive drilling ban was issued in 1990 by the current president's father, President George H W Bush, and then extended by President Bill Clinton.
Since then offshore drilling and exploration have only been allowed in the western and central regions of the Gulf of Mexico plus parts of Alaska.
The federal bans were enacted in part to protect tourism and lessen the chance of oil spills washing on to beaches.