America will be sending nuclear capable B-52 bombers to the Middle East to join the fight against the Islamic State (ISIS) jihadist group, according to defence officials.

The B-52 Stratofortress, nicknamed the "Big Ugly Fat Fella'' or BUFF, will begin dropping their deadly payload on ISIS in Iraq and Syria as early as April as they replace the B-1s that have returned to their home bases, the Air Force Times reported. It is not clear how many of the bombers or airmen will be deployed in the Middle East.

Authorities said the aircraft, which were utilised in Afghanistan to drop unguided bombs, will be used to back up warplanes that carry more precision explosives. They would be the first U.S bombers drafted in to fight the terror group.

BUFF reportedly has a payload capacity of 70,000 pounds, including gravity bombs, cluster bombs and cruise missiles. The aircraft will replace nuclear-capable B-1 Lancers, which returned to home bases in the U.S in January.

"They (B-1s) flew only 3 percent of all strike missions against ISIS, but had dropped 40 percent of the bombs and other munitions. B-1s could loiter over the battlefield for 10 hours, much longer than jet fighters, and also could fly supersonic, reaching targets across Iraq and Syria within minutes," Fox News reported.

"The B-1s are rotated out, so they're not here right now, they've gone back to do some upgrades," said Lt. Gen. Charles Q. Brown Jr., commander at U.S. Air Forces Central Command.

Lt. Gen. James "Mike" Holmes said: "We are going to keep the B-52 around. It provides some mission for us that are hard to replicate, primarily the range and payload the airplane provides.''

The aircraft first took to the skies in 1954 and regularly takes part in military exercises around the world. It can now fly at speeds of almost 650 mph. The B-52s are based in Louisiana and North Dakota.

Last Jan. 10, a single B-52 flew over South Korea following reports North Korea conducted a hydrogen bomb test, according to reports.