Donald Trump on Monday suggested that President Obama sympathized with radical Islamist terrorists, and that explained his supposed refusal to take decisive action to thwart their attacks.

“Look, we’re led by a man that either is not tough, not smart, or he’s got something else in mind, and the something else in mind — you know, people can’t believe it,” Trump said on Fox News, a day after an ISIS-inspired madman murdered 49 people and wounded 53 others at a gay club in Orlando, Fla.

“People cannot, they cannot believe that President Obama is acting the way he acts and can’t even mention the words ‘radical Islamic terrorism.’ There’s something going on. It’s inconceivable. There’s something going on,” Trump said.

“He doesn’t get it or he gets it better than anybody understands. It’s one or the other,” he added.

Trump had tweeted the day before that Obama should resign for not using the words radical Islamic terrorism in his initial statement about the atrocity at the Pulse nightclub.

In remarks Monday morning, the president used the words “perversions of Islam” in describing radical groups like Al Qaeda and ISIS — but also renewed his call for tougher gun control, a position Trump mocked.

“I mean, this man has no clue. First of all, the shooter was licensed. So he went through all the procedures, he was fully licensed to have a gun. So he would have passed the test that the president would have thrown up there. It’s so ridiculous,” he said, renewing his criticism of the country’s immigration policies and willingness to accept refugees from the war-torn Middle East.

“You know, this is a mentality, this is a state. And you have thousands of shooters like this with the same mentality out there in this country, and we’re bringing thousands and thousands of them back into this country, and into the country every year,” he said.

“We can’t let people in. … We have to be very, very strong.”

The mogul predicted that neighbors of mass killer Omar Siddiqui Mateen will come forward with knowledge of his deadly intentions.

Later Monday morning, Trump appeared on the “Today” show and was asked to explain his earlier remarks by co-host Savannah Guthrie.

“Well there are a lot of people that think maybe he [Obama] doesn’t want to get it,” the real estate tycoon said.

“A lot of people think maybe he doesn’t want to know about it. I happen to think that he just doesn’t know what he’s doing, but there are many people that think maybe he doesn’t want to get it. He doesn’t want to see what’s really happening. And that could be.”

Pressed by Guthrie to elaborate, Trump repeated his criticism of Obama for not using the words radical Islam.

“Because Savannah, why isn’t he addressing the issue? He’s not addressing the issue. He’s not calling it what it is. This is radical Islamic terrorism. This isn’t fighting Germany; this isn’t fighting Japan, where they wear uniforms,” Trump said.

Trump in the past had repeatedly questioned whether Obama was born in the US and strongly hinted that he was Muslim and not a Christian.

Although Mateen was a US-born citizen, Trump said on “Good Morning America” that the bloodbath in Orlando proved America should close its borders to Muslim immigrants.

Mateen’s parents emigrated to the US from Afghanistan, and authorities said they believe their son was self-radicalized.

“And we have to have a ban on people coming in from Syria, coming in from different parts of the world where this philosophy that is so hateful and so horrible,” Trump said.