The US President quietly signed a bill which would roll back an Obama-era regulation demanding gun checks for people with mental illnesses in February this year. The law, which was first finalised in December, aimed to add people receiving Social Security checks for mental illnesses and people deemed unfit to handle their own financial affairs to the national background check database. It would have seen 75,000 names added to the system, in a measure which sought to block some people with severe mental health problems from buying guns. READ MORE: Las Vegas MASS SHOOTING is worst in US history - 58 dead and 515 hurt in gun maniac rampage But the rule was hotly contested by gun rights advocates who said it infringed on Americans’ Second Amendment rights.

EPA - GETTY Las Vegas shooting: Donald Trump said the attack was "pure evil"

GETTY The Las Vegas attacker shot at people from the Mandalay Bay hotel

And Mr Trump quietly rolled back the bill at the end of February, after both the House and Senate last week passed the new bill H.J. Res 40 to provoke the Obama-era regulation. The National Rifle Association said it “applauded” the action, while Everytown For Gun Safety President John Feinblatt said he hoped for more gun control rollbacks from the Trump administration. But the decision could now come under fire after Sunday’s Las Vegas attack, in which at least 58 people have been killed and at least 515 injured in the deadliest mass shooting in modern US history. The 64-year-old gunman, named as local resident Stephen Paddock, fired on a Las Vegas country music festival on Sunday from the Mandalay Bay casino and hotel overlooking the world famous Strip, raining down bullets from a 32nd-floor window for several minutes before killing himself.

59 killed at Las Vegas mass shooting: Photos Tue, October 3, 2017 59 people were killed and at least 527 injured when a crazed gunman opened fire on a country music festival in Las Vegas. Play slideshow EPA 1 of 40 Las Vegas Route 91 Harvest festival mass shooting aftermath

He brutally murdered more than 50 people and wounded hundreds more. It was an act of pure evil Donald Trump

Some 22,000 people were in the crowd when Paddock opened fire, sparking a panic in which some people trampled on others in their desperate bid to escape as law enforcement officers scrambled to locate the gunman. There are no details as yet as to the gunman's motive or any reasoning behind the attack. The Islamic State has reportedly claimed the deadly mass shooting and said the attacker had converted to Islam a few months ago. Amaq news agency said: "The Las Vegas attack was carried out by a soldier of the Islamic State and he carried it out in response to calls to target states of the coalition.”

TWITTER Stephen Paddock is accused of carrying out the attack

GETTY Donald Trump thanked the police for acting so fast

But two senior US officials said on Monday that there was no evidence that the shooter was tied to any international militant group. And one said there was reason to believe that the attacker had a history of psychological problems. Police added they had no information about Paddock's motive, that he had no criminal record and was not believed to be connected to any militant group. Donald Trump has been briefed on the massacre which has the grim statistic of being the first major mass shooting of his presidency.