Good morning, NBC News readers.

Police fired tear gas at protesters in Hong Kong as outrage grew over a bill that would allow extraditions to China.

Here's what we're watching today.

Tensions flare in Hong Kong as 'one country, two systems' principle comes under threat

Huge peaceful protests descended into violent clashes in Hong Kong on Wednesday after police fired tear gas and water cannons at demonstrators hours after the government postponed a debate on a controversial extradition bill.

The proposed law would allow Hong Kong to extradite suspected criminals to mainland China.

Supporters say it's necessary to stop Hong Kong becoming a haven for fugitives, but critics argue it is the latest example of China seeking to erode Hong Kong's freedoms.

Hong Kong is a former British colony that was returned to Chinese rule in 1997. The city of 7 million people, has since been governed as a semiautonomous region under the principle of "one country, two systems."

In theory, this should allow Hong Kong to retain the economic and administrative system that has allowed it to thrive as one of the world's leading business centers, and free from Beijing's interference until 2047.

Here's more on the new law and why it has sparked such outrage.

Representatives of 22 foreign governments have spent money at Trump properties

Amid two lawsuits accusing Trump of accepting illegal foreign payments, NBC News sought to compile a comprehensive list of foreign spending at Trump properties based on public information.

The expansive list hints at a significant foreign cash flow to the American president — which critics say violates the U.S. Constitution.

'You should be ashamed'

Comedian Jon Stewart scolded Congress for failing to ensure that a victims' compensation fund set up after the Sept. 11 attacks never runs out of money.

Stewart, a longtime advocate for 9/11 responders, angrily called out lawmakers for failing to attend Tuesday's hearing on a bill that would ensure the fund can pay benefits for the next 70 years.

"They did their jobs, with courage, grace, tenacity, humility ... 18 years later, do yours!" he pleaded.

Analysis: As Biden and Trump battle in the trenches, Buttigieg attacks from higher ground

As President Donald Trump and former Vice President Joe Biden engaged in warfare on the political battlefield of Iowa on Tuesday, a third 2020 candidate found the high-ground vantage point he needed to strike both of them at the same time, NBC News Jon Allen writes in an analysis.

South Bend, Indiana, Mayor Pete Buttigieg, a veteran of the war in Afghanistan, suggested U.S. foreign policy and national security would be stuck in the past with either the president or the former vice president at the helm.

With the 2020 election season getting well underway, NBC News will be hosting the first Democratic debate over two nights on June 26-27.

What's the one question you would ask the 2020 candidates if you had the chance? Tell us here and we just might ask it.

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Plus

Texas moms hold a "nurse-in" after a breastfeeding mother was kicked out of a public pool.

"Deaths of despair" are soaring in the U.S.: The rates of deaths from suicides, drug overdoses and alcohol have reached an all-time high.

Two giraffes were killed by a "billion-to-one" lightning strike at a Florida wildlife park.

THINK about it

Hong Kong's protests against China show U.S. appeasement of Beijing has failed to bring reform, Mark Dubowitz, CEO of the Foundation for Defense of Democracies, writes in an opinion piece.

Science + Tech = MACH

The ocean’s plastic problem goes deeper than you might have realized.

Scientists using underwater robots found that plastic debris has infiltrated the deep ocean, with evidence of microscopic plastic particles extending from the surface all the way to the seafloor.

“There are efforts to try to skim plastic off the first couple of meters of the ocean’s surface, but this study shows that it’s really throughout the water column and in deeper waters,” said Emily Woglom, executive vice president of the Washington, D.C.-based nonprofit Ocean Conservancy.

Tiny plastic particles have been found in the deep ocean — and animals are eating them. Courtesy of the Monterey Bay Aquarium Research Institute / (c) 2002 MBARI

Quote of the day

"Less than 24 hours from now, I will be starting my 69th round of chemotherapy. Yeah, you heard that correct."

—Luis Alvarez, a retired New York Police Department detective who worked at Ground Zero after the fall of the Twin Towers during the House Judiciary Committee hearing on the reauthorization of the September 11th Victim Compensation Fund.

One fun thing

Team U.S.A. didn't just win their first game of the Women's World Cup, they crushed Thailand 13-0 — the largest margin of victory ever in the competition's history.

Alex Morgan scored five goals — more goals than any other team has scored in the tournament so far.

"It’s incredible, I don’t know. I’m speechless," Morgan said. "The ball just bounced my way tonight and I’m so thankful."

The Americans return to action against Chile in Paris at noon ET Sunday.

Alex Morgan and her teammates celebrate after scoring their 12th goal. Christian Hartmann / Reuters

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