Xi told Trump in a letter—which the White House distributed on Friday—that it's important the countries work together to address each other's concerns. "I hope the two sides will act in the principle and direction you and I have agreed to, and work to advance China-U.S. relations based on coordination, cooperation, and stability," the letter said.

Chinese state news agency Xinhua said negotiators made efforts toward a final agreement, but stopped short of calling Friday's outcome a deal. Hu Xijin, the editor-in-chief of China's most prominent state-run newspaper, "Global Times," noted on Twitter that official reports from China didn't mention Trump's goal of signing the deal next month, which indicates Beijing wants to keep expectations low.

Phase Two

The Trump administration also said issues related to Huawei Technologies Co. aren't part of Friday's deal and will be a separate process. The Chinese telecommunications equipment maker, which was placed on an export blacklist in May, will be discussed in a second phase of the negotiations, the president told reporters later Friday.

Equities advanced globally Friday amid growing conviction that the world's two biggest economies would negotiate a trade truce, though U.S. stocks pared gains after Trump's announcement near the close of trading. Trump tweeted earlier Friday that if the countries did reach an agreement, he would be able to sign it without a lengthy congressional approval process.

Trump's announcement drew a wary welcome from even Republicans on Capitol Hill. "After so much has been sacrificed, Americans will settle for nothing less than a full, enforceable, and fair deal with China," Senate Finance Committee Chairman Chuck Grassley said in a statement after the announcement. "Farmers in Iowa know far too well that the trade war has caused real financial pain in the heartland. But we need to know more about this deal, and follow-through from China will be key."

On Thursday and earlier Friday, Liu and U.S. Trade Representative Robert Lighthizer held the first senior-level discussions between Washington and Beijing since a previous agreement fell apart in May and tariffs were raised in the months after.

What Bloomberg Economists Say

"Past experience is that U.S.–China trade agreements aren't worth the paper they are written on, and this one hasn't even been written down. For now, though, indications on trade are a little more positive. If that persists, it could help put a floor under sliding global growth."

— Tom Orlik and Yelena Shulyatyeva, Bloomberg Economics

The U.S. was threatening to increase tariffs on Tuesday on about $250 billion of Chinese imports, from 25 percent to 30 percent. More duties on $160 billion of Chinese products were targeted for Dec. 15.

The threat of those import taxes on U.S. consumers, falling around the holiday season, raised the prospect that the U.S. economy would slide toward a recession heading into Trump's 2020 re-election bid. The American manufacturing industry, which Trump vowed in 2016 to revitalize, is already contracting, in part because of the trade war.

The Trump administration said that as part of the deal, China would scale up its purchases of U.S. farm goods over two years, to an annual total of $40 billion to $50 billion. Trump encouraged U.S. farmers to buy more land and Deere & Co. tractors in response.

In recent weeks, China had already discussed buying more U.S. products such as soybeans, pork, and wheat. Some traders remained skeptical that buying soybeans from the U.S. represented a significant breakthrough in the overall trade talks, Bloomberg reported Friday.

Earlier Friday, Trump indicated in a Twitter post that if the countries did reach an agreement, he would be able to sign it quickly.

One of the great things about the China Deal is the fact that, for various reasons, we do not have to go through the very long and politically complex Congressional Approval Process. When the deal is fully negotiated, I sign it myself on behalf of our Country. Fast and Clean!  — Donald J. Trump (@realDonaldTrump) October 11, 2019

Senator Ronald Wyden, the ranking Democrat on the Finance Committee that has jurisdiction over trade policy, pushed back on Trump's tweet in a statement Friday to Bloomberg News: "Donald Trump should know that any meaningful trade deal is only legitimate because of the authority granted to him by Congress, and that authority can be taken away," he said.

Under the U.S. Constitution, Congress holds power over international trade. For decades, it has legally delegated trade-negotiating authority to the executive branch. Lawmakers in recent months have grown increasingly wary of what they see as Trump's abuse of that authority and discussed ways to claw it back, citing the president's many unilateral tariff measures and a lack of transparency in negotiations.

—With assistance from Jennifer Jacobs, Ye Xie, Isis Almeida, Scott Lanman, Sophie Caronello, and Sarah McGregor.

Copyright 2019 Bloomberg. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed.