Good morning, NBC News readers.

President Donald Trump lived up to his promise to increase U.S. tariffs on Chinese imports — escalating the trade war between the world's two largest economies.

Here's what else we're watching.

Iran denies making threat as U.S. ramps up pressure

Iran's ambassador to the United Nations on Thursday rejected allegations that Tehran had given a green light to its proxies to attack U.S. forces in the Middle East, accusing American officials of employing "fake intelligence."

Ambassador Majid Takht Ravanchi told NBC News' Andrea Mitchell that the Trump administration's allegations of warmongering were false and being spread by "the same people" who pushed the U.S. into Iraq.

Trump said on Thursday that his administration had information Iran was "threatening" the United States, but provided no further details.

Meantime, Trump's top intelligence and military advisers recently held a highly unusual 7 a.m. Monday morning meeting at CIA headquarters on Iran.

Half a dozen current U.S. officials, as well as multiple former officials, said it is extremely rare for senior White House officials or Cabinet members to attend a meeting at CIA headquarters.

U.S. increases China tariffs, escalating trade war

After days of threats, the Trump administration's tariff hikes on $200 billion worth of Chinese imports took effect Friday.

The move came after trade negotiations with the Chinese failed.

It escalates tensions with Beijing, which vowed to take "necessary countermeasures" but gave no details as to what they would be.

The two sides will resume talks today.

A round of golf helped seal the deal on defense secretary nomination

The president is expected to nominate former Boeing executive Patrick Shanahan as secretary of defense — despite his concerns that he does not fit the mold of a battle-hardened general, officials said.

A golf course chat with Sen. Lindsey Graham helped convince Trump that the acting Pentagon chief was up to the job, officials familiar with the matter told NBC News.

If confirmed by the Senate, Shanahan would join more than half a dozen others who led the department without having served in the military.

Analysis: Pelosi's impeachment approach is coming together

The president's recent actions have helped Speaker Nancy Pelosi, D-Calif., start to resolve the conflicts in her caucus — and unite them around a deliberate, relentless investigative approach, NBC News Jonathan Allen writes.

"This is very methodical, it's very Constitution-based, it's very law-based, it's very factually based," Pelosi said about House plans to hold Attorney General William Barr in contempt for withholding documents. "It's not about pressure. It's about patriotism."

The Week in Pictures

Students are evacuated during the shooting at the STEM School Highlands Ranch in Colorado on Tuesday. Michael Ciaglo / Getty Images

See some of the most compelling images from the last week.

Want to receive the Morning Rundown in your inbox? Sign up here.

Plus

North Korea tested "multiple ballistic missiles" in its latest launch, the Pentagon said.

"We're setting our kids up to be martyrs": In two recent incidents, students tackled shooters and died as heroes. But some safety experts and psychologists say we're putting unfair expectations on our children.

A group of San Francisco parents have rallied around a teacher battling breast cancer who was required to pay out of her own pocket for her classroom's substitute while she was on medical leave.

Science + Tech = MACH

"This vehicle is going to the moon," said billionaire Jeff Bezos as he unveiled his space company's lunar lander for the first time on Thursday.

Live BETTER

A self-employed writer shares three productivity hacks she says helped her boost her income by 65 percent.

Quote of the day

"These are all allegations which are being produced by the same people who, in the run-up to the U.S. invasion of Iraq, did the same."

— Iran's ambassador to the United Nations Majid Takht Ravanchi

One fun thing

TV for free? In the Netflix era, Pluto TV offers a wallet-friendly pitch.

You still have to put up with old-fashioned commercial breaks, but the service offers the television equivalent of comfort food: throwback sitcoms, vintage movies, reality shows and nature specials.

To some viewers it offers a bit of nostalgia. “It reminds me of the antenna TV we had when I was a little kid," said one fan.

Vinnie Neuberg / for NBC News

Thanks for reading the Morning Rundown.

If you have any comments — likes, dislikes — drop me an email at: petra@nbcuni.com

If you'd like the Morning Rundown in your inbox Monday to Friday, please sign up here.

Thanks, Petra