Royal Dutch Shell has won approval from the US Government to explore for oil in the Arctic.

The company wants to drill up to six wells around 40 metres deep.

However, a condition of the approval means Shell “must still obtain all necessary permits from other state and federal agencies”, the Bureau of Ocean Energy Management (BOEM) said.

Abigail Ross Harper, Director of BOEM added: “We have taken a thoughtful approach to carefully considering potential exploration in the Chukchi Sea.

“As we move forward, any offshore exploratory activities will continue to be subject to rigorous safety standards.”

Shell has spent around $6billion (£3.85bn) on exploration in the Arctic. The region is estimated to have 20% of the world’s undiscovered oil and gas.

Shell spokesman Curtis Smith said in an email: “[The approval] is an important milestone and signals the confidence regulators have in our plan.

“However, before operations can begin this summer, it’s imperative that the remainder of our permits be practical and delivered in a timely manner.

“In the meantime, we will continue to test and prepare our contractors, assets and contingency plans against the high bar stakeholders and regulators expect of an Arctic operator.”

Environmental campaigners opposed the move.

Marissa Knodel from Friends of the Earth said: “It is unconscionable the federal government is willing to sacrifice the health and safety of the people and wildlife of the Chukchi Sea to Shell’s reckless pursuit of profit.

“The Obama administration should know better: we deserve a clean legacy that leaves fossil fuels in the ground, not another toxic legacy from Big Oil.”

Last month Greenpeace activists climbed aboard Shell’s oil rig to protest against its plans to drill in the Arctic.

• Alaska, drilling, oil, USA