The United States has lifted a ban on deepwater drilling in the Gulf of Mexico imposed after the BP oil spill, but set operators tough new safety conditions, officials said.

“We have decided it is now appropriate to lift the suspension on deepwater drilling for those operators that are able to clear the higher bar that we have set” for safety, Interior Secretary Ken Salazar said.

President Barack Obama ordered a six-month freeze on deepwater offshore oil drilling in the Gulf of Mexico shortly after a blowout on the BP Deepwater Horizon undersea well that killed 11 rig workers and sparked the worst oil disaster in US history.

The moratorium was due to expire at the end of next month.

The new rules, which were laid out by the Interior Department two weeks ago, toughen up companies’ obligations on drilling and workplace safety, well containment and spill response, said Salazar.

Key among the tough new rules is an obligation for the CEO of any company wishing to drill in deep water to “certify that the rig has complied with all new and existing rules,” he said.

Executives from the companies involved in the BP-leased well that blew out have blamed each other for the accident which happened some 80 kilometres off the coast of Louisiana.

But even if the moratorium was being lifted, deepwater drilling was not expected to resume soon, said Michael Bromwich, director of the Bureau of Ocean Energy Management, Regulation and Enforcement (BOEM).

Oil and gas companies need time to implement the new rules and draw up applications for offshore leases “and it will obviously take us time to review those applications and do due diligence,” said Mr Bromwich.