BEIRUT (AFP) - Syria's Al-Qaeda affiliate has released a video of a US suicide bomber who blew himself up at an army post in the northwest of the country.

Moner Mohammad Abu Salha, alias Abu Hurayra al-Amriki, was believed to be the first American national to carry out such an attack in Syria's more than three-year-old war.

"I want to rest in the afterlife, not in this world... My heart is not at peace here. Hopefully it will be in heaven," Abu Hurayra says in broken Arabic in the 17-minute video posted on YouTube on Friday by Al-Nusra Front.

The footage, released via Al-Nusra's official channel Al-Manara Al-Baydaa, also shows Abu Hurayra saying: "I came to Syria without money to buy a rifle or a pouch.

"God gave me a rifle and a pouch and everything, and... (then) he gave me even more."

The American jihadist carried out a May 25 truck bomb attack on an army base in Jabal al-Arbaeen area of northwest Syria's Idlib province.

Six days, the State Department confirmed that the US citizen, who newspapers said was from Florida and travelled to Syria in 2013, had carried out a suicide attack.

Estimates of the number of foreign fighters who have flooded into Syria in the past three years range from between 9,000 to 11,000.

The video gives few details about Abu Hurayra's precise background, but shows him alongside three other suicide bombers, seated near an Al-Nusra black flag, each speaking of their mission.

At the time, the Syrian Observatory for Human Rights said four suicide attacks on army positions in Idlib on May 25 left dozens of casualties.

The video says Abu Hurayra attacked an army command building, while a jihadist from the Maldives was also among the four bombers.