President Trump would have “maybe 10 minutes” to decide whether to launch a retaliatory strike against North Korea — should it ever fire a missile that’s capable of reaching the US mainland, experts say.

Speaking to the Associated Press about what would happen in the event of a nuclear strike from the North, scientist David Wright, of the UCS Global Security Program, and rocket analyst Markus Schiller, of ST Analytics in Germany, described how the drama would unfold.

“The timelines are short,” Wright explained. “Even for long-range missiles, there are a lot of steps that go into detecting the launch and figuring out what it is, leaving the president with maybe 10 minutes to decide whether to launch a retaliatory strike.”

While experts insist that North Korea is still not capable of launching a missile that could reach the United States, the communist nation on Monday claimed it could.

Its state-run KCNA news service alleged that it now has the ability to send a “large-size heavy nuclear warhead” across the Pacific following its test of a Hwasong-12 missile over the weekend.

But Kim Dong-yub, professor at South Korea’s Kyungnam University, told local media that they’d be lucky to reach Alaska or Hawaii, at best.

If they did have the capability of hitting US targets, though, Wright and Schiller predict that things could get out of hand — and fast.

While Wright believes an intercontinental ballistic missile fired from the Hermit Kingdom would take a little over a half-hour to reach San Francisco, Schiller said he believes one could strike Seattle or Los Angeles less than 30 minutes after launch.

New York and Washington, at less than 6,800 miles away, would likely have between 30 and 40 minutes before being hit, Schiller and Wright said.

American allies around the Korean Peninsula will have an even shorter window, should leader Kim Jong Un decide to attack his neighbors in the South Pacific.

People living in Seoul would essentially have zero to 6 minutes — from the moment a missile is launched to the time it hits the target — to take cover in the event of a strike, Schiller and Wright said.

Those in Japan will have a little more time to prepare, but not much. Schiller and Wright estimate that it would take 10 to 11 minutes before a missile from the North reached Tokyo.

Then there’s the added risk of Kim using chemical or biological warheads, while also unleashing a “swarm” attack on South Korea and Japan — using medium-range Scud ER missiles, which were tested back in March.

While defense systems are in place to defend against such assaults, Schiller and Wright warned that they could wind up failing or prove worthless against artillery strikes and multiple projectiles.

The pair told the AP that if the North ultimately thought it was under immediate attack or threatened, one possible scenario would be that it would first target the South Korean city of Busan, which is often used as a port by the US Navy.

From that point on, it is unclear what would likely be the next step — but if Trump did decide to fire back, Schiller and Wright said he could have land-based ICBMs in the air within five minutes, and submarine-based missiles in 15.

With Post wires