Donald Trump has picked Oklahoma Attorney General Scott Pruitt to head the Environmental Protection Agency(EPA) despite the fact he has led lawsuits against the federal body.

Mr Pruitt, a close ally of the oil and gas industry, has been one of the EPA's fiercest critics during Barack Obama's administration, describing it as "unlawful and overreaching".

He has attacked President Obama for allegedly trying to prevent two thirds of fossil fuels "in the ground" being used as an energy source.

Mr Pruitt has repeatedly cast doubt on climate change, saying the science behind it was “subject to considerable debate”.

As part of a coalition of state attorney generals, Mr Pruitt sued the EPA's Clean Power Plan, which aimed to reduce US greenhouse gas emissions from electricity production.

Mr Pruitt also sued the agency, again with fellow state attorney generals, over newly announced EPA regulations that seek to control the emissions of methane from the oil and gas sector.

On announcing his decision, Donald Trump said: "For too long, the Environmental Protection Agency has spent taxpayer dollars on an out-of-control anti-energy agenda that has destroyed millions of jobs, while also undermining our incredible farmers and many other businesses and industries at every turn.

He said the Oklahoma attorney general "will reverse this trend and restore the EPA’s essential mission of keeping our air and our water clean and safe".

"My administration strongly believes in environmental protection, and Scott Pruitt will be a powerful advocate for that mission while promoting jobs, safety and opportunity", he added.

Donald Trump's most controversial quotes Show all 14 1 /14 Donald Trump's most controversial quotes Donald Trump's most controversial quotes On Isis: "Some of the candidates, they went in and didn’t know the air conditioner didn’t work and sweated like dogs, and they didn’t know the room was too big because they didn’t have anybody there. How are they going to beat ISIS?" Getty Donald Trump's most controversial quotes On immigration: "I will build a great wall — and nobody builds walls better than me, believe me —and I’ll build them very inexpensively. I will build a great, great wall on our southern border, and I will make Mexico pay for that wall. Mark my words." Reuters Donald Trump's most controversial quotes On Free Trade: "Free trade is terrible. Free trade can be wonderful if you have smart people. But we have stupid people." PAUL J. RICHARDS | AFP | Getty Images Donald Trump's most controversial quotes On Mexicans: "When Mexico sends its people, they’re not sending their best. They’re sending people that have lots of problems. They’re bringing drugs. They’re bringing crime. They’re rapists." Getty Donald Trump's most controversial quotes On China: "I just sold an apartment for $15 million to somebody from China. Am I supposed to dislike them?... I love China. The biggest bank in the world is from China. You know where their United States headquarters is located? In this building, in Trump Tower." Getty Images Donald Trump's most controversial quotes On work: "If you're interested in 'balancing' work and pleasure, stop trying to balance them. Instead make your work more pleasurable." AP Donald Trump's most controversial quotes On success: "What separates the winners from the losers is how a person reacts to each new twist of fate." Donald Trump's most controversial quotes On life: "Everything in life is luck." AFP Donald Trump's most controversial quotes On ambition: "You have to think anyway, so why not think big?" Getty Images Donald Trump's most controversial quotes On his opponents: "Bush is totally in favour of Common Core. I don't see how he can possibly get the nomination. He's weak on immigration. He's in favour of Common Core. How the hell can you vote for this guy? You just can't do it." Reuters Donald Trump's most controversial quotes On Obamacare: "You have to be hit by a tractor, literally, a tractor, to use it, because the deductibles are so high. It's virtually useless. And remember the $5 billion web site?... I have so many web sites, I have them all over the place. I hire people, they do a web site. It costs me $3." Getty Images Donald Trump's most controversial quotes On Barack Obama: "Obama is going to be out playing golf. He might be on one of my courses. I would invite him. I have the best courses in the world. I have one right next to the White House." PA Donald Trump's most controversial quotes On himself: "Love him or hate him, Trump is a man who is certain about what he wants and sets out to get it, no holds barred. Women find his power almost as much of a turn-on as his money." Getty Images Donald Trump's most controversial quotes On America: "The American Dream is dead. But if I get elected president I will bring it back bigger and better and stronger than ever before and we will make America great again." GETTY

The President-elect's own statements on climate change during the campaign have caused consternation and worry among environmentalists, seeing him describe global warming as "a hoax" that was "invented by and for the Chinese".

After he won the election in November, the billionaire businessman did appear to undergo an U-turn on the issue when he admitted in a news conference "there was some connectivity" between human activity and climate change.