GEOFF BENNETT: Welcome to the "News Hour."

It was a day of wild swings on Wall Street, as investors and businesses sought clarity about the scope of new tariffs and how long they might last.

AMNA NAWAZ: President Trump and his team sent conflicting messages again, including a threat by the president to ramp up much larger tariffs of 50 percent against China.

By day's end, the Dow finished a bit down, just under 1 percent.

The Nasdaq finished just above break-even, and the S&P 500 was down about two-tenths of a percent.

But turmoil and confusion over the president's goals defined much of the day.

Lisa Desjardins has our report.

(BELL RINGING) LISA DESJARDINS: The opening bell on Wall Street, the sound of alarm, with stocks bungeeing wildly in the first hours and traders not able to find a foothold in President Trump's tariff war.

The economic issues are complicating diplomatic ones, as Israeli Prime Minister Benjamin Netanyahu arrived at the White House.

QUESTION: Mr. President, will you discuss tariffs on Israel?

LISA DESJARDINS: Reporters shouted questions after the two leaders canceled their formal news conference together.

Netanyahu's war-battered economy now faces a new 17 percent tariff from the U.S. DONALD TRUMP, President of the United States: But we had great discussions today.

LISA DESJARDINS: In the Oval Office, Israel's leader said his country will meet Trump's economic demands.

BENJAMIN NETANYAHU, Israeli Prime Minister: We will eliminate the trade deficit with the United States.

We intend to do it very quickly.

We think it's the right thing to do, and we're going to also eliminate trade barriers, a variety of trade barriers that have been put up unnecessarily.

LISA DESJARDINS: The president used the opportunity to dig in on tariffs.

DONALD TRUMP: This is America first.

It's now America first.

And we didn't put America first.

We put America last.

LISA DESJARDINS: Trump actually upped the stakes, threatening China on social media with another 50 percent tariff if the world's second largest economy does not back off its reciprocal tariffs by tomorrow, this as words of warning are growing more urgent.

Across the Atlantic, European Commission President Ursula von der Leyen accused the U.S. of economic bullying and said it is now talking with other trading partners.

URSULA VON DER LEYEN, President, European Commission: So it's very clear that we are open for negotiations and that, in parallel, we are preparing a potential list for retaliation and other measures for retaliation if this is necessary.

We prefer to have a negotiated solution.

LISA DESJARDINS: Back on Wall Street, billionaire Trump backer and hedge fund manager Bill Ackman urged Trump to delay large tariff deadlines, writing: "Otherwise, we are heading for a self-induced, economic nuclear winter and we should start hunkering down."

And J.P. Morgan CEO Jamie Dimon warned the bank's investors of higher prices in the short term and adding: "Whether or not the menu of tariffs causes a recession remains in question."

This after a morning of whiplash on the markets, first plunging and then a sudden rise back into positive territory based on a social media-fueled rumor.

National Economic Council chief Kevin Hassett was asked this on FOX News.

BRIAN KILMEADE, FOX News Anchor: Will you do a 90-day pause?

Would you consider that?

KEVIN HASSETT, Director, National Economic Council: The president is going to decide what the president's going to decide.

The idea that it's going to be a nuclear winter or something like that, it's completely irresponsible rhetoric.

LISA DESJARDINS: Some on social media mistakenly proclaimed a 90-day tariff freeze was coming, leading to a sudden positive spike that quickly disappeared.

To the idea of a 90-day pause, today Trump himself told reporters: DONALD TRUMP: Well, we're not looking at that.

We have many, many countries that are coming to negotiate deals with us and they're going to be fair deals.

LISA DESJARDINS: That seemed to contradict with other words of Trump's advisers, including counselor Peter Navarro yesterday on FOX.

PETER NAVARRO, Director, White House Office of Trade and Manufacturing Policy: This is not a negotiation.

LISA DESJARDINS: Today, the president was asked.

QUESTION: You're talking about negotiations, and yet others in your administration are saying that these tariffs are actually permanent.

What is the actual strategy?

DONALD TRUMP: Well, it can be -- it can both be true.

There can be permanent tariffs and there can also be negotiations.

LISA DESJARDINS: A few on Trump's team have repeated a more specific phrase about the length of the tariffs.

HOWARD LUTNICK, U.S. Commerce Secretary: They are definitely going to stay in place for days and weeks.

That is sort of obvious.

The president needs to reset global trade.

LISA DESJARDINS: The effect on global trade long-term is not yet clear.

But the world's stock markets continue to reset to red.

For the "PBS News Hour," I'm Lisa Desjardins.