A senior White House official said Tuesday that "all options" are on the table to curb the country's nuclear weapons programs. Over the weekend, Trump told the Financial Times he would be willing to take on North Korea unilaterally.

Trump has long honed in on North Korea as one of the biggest threats facing the United States. Over the past two decades, he has at times even suggested bombing North Korea's nuclear facilities.

When Trump explored a presidential run back in 1999, he wrote an op-ed in The Wall Street Journal in which he suggested he would bomb North Korea if it didn't end its nuclear weapons program.

"I would let Pyongyang know in no uncertain terms that it can either get out of the nuclear arms race or expect a rebuke similar to the one Ronald Reagan delivered to Muammar Gadhafi in 1986," he wrote, referring to the U.S. bombing of Libya under Reagan's administration.

Trump followed up those comments with a passage about North Korea in his 2000 book, "The America We Deserve." In the book, Trump called US policy towards North Korea "weak-minded," and explicitly said he would bomb the country's nuclear facilities.

"Am I ready to bomb this reactor? You're damned right," Trump wrote. "When the Israelis bombed the Iraqi nuclear reactor they were condemned by the world community. But they did what they had to do to survive. The Korean nuclear capability is a direct threat to the United States. As an experienced negotiator, I can tell you that negotiation with these madmen will be fruitless once they have the ability to lob a nuclear missile into Chicago, Los Angeles, or New York. I don't advocate a thermonuclear war, but if negotiations fail, I advocate a surgical strike against these outlaws before they pose a real threat."

In the book, Trump also dismissed concerns about nuclear fallout from the strike.

"When I advocated the possibility of a surgical strike against the North Koreans on Meet the Press, moderator Tim Russert asked me about the possibility that nuclear fallout might pollute Asia as a consequence of our taking action. Russert quoted a former secretary of defense saying that a surgical strike was not an option for this reason. After all, Israel attacked a similar facility in Iraq with no fallout. (Within days of the Meet the Press broadcast I had two phone calls from officers very high up in our military who both assured me— off the record— that such a strike could be successful. Because both men are still on active duty, neither one wants to be identified.)"

Throughout the 2000s, Trump would identify North Korea as an area of concern. In January 2003, Trump said on Fox News, "North Korea may be a bigger problem than Iraq." Three years later, Trump told CNN that the US should get out of Iraq, especially with Iran and North Korea developing nuclear weapons.

More recently, Trump has proposed putting pressure on China to deal with North Korea. The issue is expected to be a topic of discussion when Chinese President Xi Jinping meets with Trump on Thursday.

In a 2015 interview with "60 Minutes" Trump was asked about his prior calls for a strike on North Korea's nuclear facilities.

"You would drop a bomb on their nuclear reactor?" asked Scott Pelley.

"I would do something," Trump responded. "You have to do something about North Korea. Now, what I would do is I would make China respect us because China has extreme control over North Korea."

He added, "And if they don't do that, they have to suffer economically because we have the engine that makes China work. You know, without the United States or without China sucking out all our money and our jobs, China would collapse in about two minutes."