Amid rising tensions with North Korea, the US Air Force is preparing to put its nuclear-armed B-52 bombers back on 24-hour alert — a status not seen since the end of the Cold War in 1991, according to a report.

A return to a 24-hour alert would mean the venerable bombers would once again park at the long-dormant pads of Barksdale Air Force Base in Louisiana — dubbed the “Christmas tree” for their angular markings, Defense One reported.

“This is yet one more step in ensuring that we’re prepared,” Air Force chief of staff Gen. David Goldfein told the industry publication during his tour of Barksdale and other bases that support the nuclear mission.

“I look at it more as not planning for any specific event, but more for the reality of the global situation we find ourselves in and how we ensure we’re prepared going forward,” he said.

Goldfein and other top defense officials stressed that the alert order had not been given — just that preparations were under way in case it might be.

Such a decision would be made by Gen. John Hyten, head of US Strategic Command, or Gen. Lori Robinson, head of US Northern Command, according to Defense One.

STRATCOM is in charge of the military’s nuclear forces and NORTHCOM is in charge of defending North America.

Goldfein said that in a world where “we’ve got folks that are talking openly about use of nuclear weapons,” it’s important to be vigilant and proactive.

“It’s no longer a bipolar world where it’s just us and the Soviet Union. We’ve got other players out there who have nuclear capability. It’s never been more important to make sure that we get this mission right,” Goldfein said, Fox News reported.

Barksdale Air Force Base, home of the 2nd Bomb Wing and Air Force Global Strike Command, which manages the service’s nuclear services, is being renovated so the B-52s would be ready to “take off at a moment’s notice,” according to the publication.

The B-52 — also called the Stratofortress — can fly up to about 50,000 feet and release a variety of weapons, including cluster bombs, gravity bombs and precision guided missiles.

According to Defense One, two nuclear command planes, the E-4B Nightwatch and E-6B Mercury, will be deployed to Barksdale. During a nuclear war, they would serve as flying command posts of the defense secretary.

Putting the fleet back on alert is one of many decisions facing the Air Force as the US military responds to the hermit kingdom’s nuclear tests and President Trump’s combative approach to Pyongyang.

Tensions have skyrocketed on the peninsula after a series of weapons tests by the rogue regime and increasingly bellicose exchanges between Trump and despot Kim Jong Un.

Recently, Trump cryptically warned about the “calm before the storm” after a White House meeting with US military leaders.