The world is no safer 15 years after the US-led invasion of Afghanistan and the killing of Osama bin Laden did not change the war very much, veteran journalist Seymour Hersh told Al Jazeera on the fifth anniversary of the killing of al-Qaeda's leader.

The al-Qaeda leader was killed in a US raid in Abbottabad, Pakistan, in 2011, an event that is a "fantasy", according to Hersh.

"The president did authorise the killing and the [Navy] Seals did kill bin Laden. Everything after that is sort of a fantasy, it's Lewis Carroll," Hersh said.

"But the killing of bin Laden didn't seem to change the war very much."

Hersh said the US is struggling to win the longest war in its history.

"The Americans declared a war on terror and look at where we are now ...15 years later still fighting in Afghanistan."

The famed US journalist, known for his expose of US war crimes in Vietnam, said the US was hiding key facts about the raid that killed the al-Qaeda leader.

The CIA said the mission in Pakistan was the "culmination of years of complex, thorough and highly advanced intel operations and analyses", in a series of tweets posted on Monday, describing the operation as a "significant victory" in the war against al-Qaeda.

The CIA "live tweeted" the military raid that killed bin Laden five years ago, drawing derision and satire from many people on Twitter.

US account disputed

Crucially, US officials stated that the Pakistani government and intelligence service were not informed about the operation, a claim Hersh has disputed.

"We had a disgruntled Pakistani intelligence officer come to our embassy in the summer of 2010 and tell us 'My God! The Pakistanis have parked this guy in this town'," Hersh said.

"We [the US] eventually worked it out and made an agreement and accommodation with the Pakistani military and intelligence services that we would go with their help and take out the guy.

"The idea that he was there without the [knowledge] of the Pakistani intelligence service, in particular, the ISI [Inter-Services Intelligence] and the Pakistani military, is just comical."

Hersh said the mistakes of the George Bush administration continued to be made by the current US President Barack Obama, citing his continued use of drones and his involvement in Syria.