President Trump has pulled out of a historic summit in Singapore with North Korean Leader Kim Jong Un, which had been scheduled for June 12, calling it "a truly sad moment in history."

In an open letter, Trump told Kim "we greatly appreciate your time, patience, and effort with respect to our recent negotiations" and that "I was very much looking forward to being there with you," but that "it is inappropriate, at this time, to have this long-planned meeting" due to increasing tensions between the parties. A North Korean vice minister of foreign affairs called Vice President Mike Pence "ignorant" and "stupid" on Thursday for comparing North Korea to Libya, and warned Kim would cancel the summit if the U.S. didn't stop its threats.

Read the letter in full below. Jeva Lange

President Trump on Friday tweeted an announcement that Mick Mulvaney, Director of the Office of Management and Budget, will step in as acting White House chief of staff.

Mulvaney, who also worked as the acting director of the Consumer Financial Protection Bureau before bowing out this week, will replace current White House Chief of Staff John Kelly, who will depart at the end of the year. "Mick has done an outstanding job while in the administration," wrote Trump, "I look forward to working with him in this new capacity."

Trump additionally praised Kelly as a "great patriot" who "served our country with distinction." Trump's reported first choice to replace Kelly, Vice President Mike Pence's chief of staff Nick Ayers, turned down the job, leaving Trump to consider several administration officials and lawmakers for the post. Summer Meza

Gun deaths in the U.S. reached their highest point in nearly 40 years in 2017, according to a CNN analysis of a report released by the Centers for Disease Control and Prevention.

The CDC's data showed that nearly 40,000 people died by gun last year, CNN reports, which is up from 28,874 in 1999. CNN's analysis also found that more than 23,000 people died from suicide by guns, which is the highest rate in 18 years.

The report found that white men led the gender and racial demographics for gun deaths by suicide, and black men led in homicide deaths.

Former U.S. Rep. Gabrielle Giffords (D), who was nearly killed in 2011 due to a gun wound, released a statement reacting to the CDC's report.

"This data from the CDC reminds us how many lives our gun violence crisis alters every year – and why so many Americans are rising up to demand action," Giffords said. "It's unacceptable that the number of deaths from shootings keeps escalating while Washington, D.C. refuses to even debate policies we know would help save lives." Marianne Dodson

People are using the highest levels of government to come up with the world's lowest security passwords.

More than 5 million passwords were leaked this year, password manager SplashData's analysis of breached data reveals. Your standard "iloveyou" and "qwerty" made the list of the most popular passwords in the world, but so did one newcomer: "donald."

Of all the infinite combinations of letters, numbers, and symbols people could use, nearly 10 percent of internet users secured their accounts with one of the 25 worst passwords out there, per TechCrunch. After "123456" and "password," strings of numbers make up the next five "worst passwords" on SplashData's list. And making its first-ever top-25 appearance, clocking in at No. 23, is "donald."

No, SplashData's CEO assures us "this is not fake news." Hackers find "celebrity names" and other common words are often used as passwords, as are simple keyboard strings. So try passwords of at least 12 characters, and mix in some symbols and numbers, SplashData recommends. And whatever you do, don't use anything on the list below, as compiled by TechCrunch. Kathryn Krawcyzk

A DC comic series has been axed after allegations of sexual abuse emerged against its writer.

The series Border Town will cease production, and the final two issues of the comic will not be published under DC, The Hollywood Reporter wrote on Friday. The announcement comes after toy designer Cynthia Naugle published a statement saying she had been "sexually, mentally, and emotionally abused" by an unnamed person. The figure was later identified on social media as Border Town writer and co-creator Eric M. Esquivel, per the Reporter.

Two artists for the comic have since released statements on Twitter, with color artist Tamra Bonvillain calling Esquivel's actions "disgusting and inexcusable." Esquivel has not yet publicly commented on the allegations.

Border Town opened this year's relaunch of the DV Vertigo line, which publishes more mature content about hot button topics. The comic sold out and was met with critical acclaim, per the Reporter. Marianne Dodson

Wisconsin Gov. Scott Walker (R) signed legislation Friday stripping some powers from his Democratic replacement, and in the process, revealed his misunderstanding of a very elementary math concept.

Ever since Wisconsin's GOP lost the executive branch but retained the legislative one, lawmakers and the outgoing Walker have embarked on a lame-duck quest to limit the incoming administration's powers. Legislation passed by the state's legislature and signed Friday by Walker will stop governor-elect Tony Evers (D) from controlling a state economic commission and reduces time for early voting, among other things. It's very "inside baseball," as the state Senate's majority leader said, so Walker tried to explain it in a Venn Diagram.

Graduates of middle school math would notice all the "authorities" listed on both sides of the graph should go in the middle, and all the executive powers Walker just signed away should be listed only in his. But to be fair, "not understanding the most basic of graphs" is something both Democrats and Republicans could put between their two circles in a Venn diagram. Kathryn Krawczyk

George Papadopoulos doesn't see why being sent to jail for lying to the FBI should get in the way of his plans to run for Congress.

The former foreign policy adviser to President Trump's campaign told The Telegraph on Friday that he will run for Congress in 2020, saying he always intended to use his connection with Trump "as a platform to run for office myself." Papadopoulos said his "end game remains the same," even though "things just took a different direction," by which he means he was convicted for lying to federal investigators and is on supervised release for the next year.

He didn't specify where he's going to run, but it sounds like he's not picky, saying, "I just have to find a little Republican enclave somewhere in this part of the world, in this part of the country I should say, and run there." In fact, he claims he already has "some support."

On Twitter, Papadopoulos doubled down, tweeting a simple message to those who have suggested the best time to launch a congressional bid isn't necessarily seven days after getting out of jail: "It is true," he wrote. "I will be running for Congress in 2020, and I will win. Stay tuned." Brendan Morrow