WASHINGTON — The Obama administration Tuesday lifted a moratorium it imposed on deep-water offshore oil drilling in July during the BP oil spill in the Gulf of Mexico, saying that new rules should make it safer.

While all work isn’t expected to resume immediately, the timing of the announcement — six weeks ahead of schedule and three weeks before congressional and state elections — could give Democrats a boost at the polls.

The moratorium has been blamed for thousands of lost jobs in an already damaged economy and posed a potential drag on some Democrats’ election prospects.

Both candidates in the Louisiana Senate race, Republican David Vitter and Democratic Rep. Charlie Melancon, have criticized the moratorium. Sen. Mary Landrieu, D-La., has been holding up Senate confirmation of President Barack Obama’s nominee to head the Office of Management and Budget, Jacob Lew, to protest the moratorium.

Interior Secretary Ken Salazar, announcing the move in a teleconference, said he expects criticism from both camps: industry interests who say the new standards are too onerous and drilling opponents who say the moratorium is being lifted too soon.

To the latter group, Salazar said, “”The truth is, there will always be risks associated with deep-water drilling. But we have now reached a point where we have significantly, in my view, reduced those risks.””

Even as the nation seeks more clean-energy alternatives, Salazar said, “”We will still need oil and gas from the Gulf of Mexico to power our cars, our homes and our industry. But we can and we will make the drilling of oil and gas in the Gulf of Mexico safer than it ever has been.””

The new rules, issued two weeks ago, include requirements for worst-case planning requirements and third-party verification that blowout preventers and other equipment work properly. Oil rig operators also will be required to show they have enough materials to contain oil in the case of a blowout.

The BP spill began April 22 after an explosion on the Deepwater Horizon rig, and it took until July 15 to stop the flow of oil from a well nearly a mile underwater. An estimated 4.1 million barrels of oil flowed into the Gulf in the nation’s worst man-made environmental disaster.