President Donald Trump says he has suspended plans to impose tariffs on Mexico, tweeting that the country “has agreed to take strong measures” to stem the flow of Central American migrants into the United States.

“I am pleased to inform you that The United States of America has reached a signed agreement with Mexico,” Trump tweeted Friday night, saying the “Tariffs scheduled to be implemented by the U.S. on Monday, against Mexico, are hereby indefinitely suspended.”

He said Mexico has agreed to work to “stem the tide of Migration through Mexico, and to our Southern Border” and said those steps would “greatly reduce, or eliminate, Illegal Immigration coming from Mexico and into the United States.”

According to a “U.S.-Mexico Joint Declaration” released by the State Department late Friday, the U.S. said it will work to greatly expand a program that returns asylum-seekers who cross the southern border to Mexico while their claims are adjudicated.

Mexico has also agreed to take “unprecedented steps to increase enforcement to curb irregular migration,” including the deployment of the Mexican National Guard throughout the country, especially on its southern border with Guatemala. And the U.S. said Mexico is also taking “decisive action to dismantle human smuggling and trafficking organizations as well as their illicit financial and transportation networks.”

Trump's decision marked a change in tone from earlier Friday when his spokeswoman Sarah Sanders told reporters in Ireland before Trump took off: “Our position has not changed. The tariffs are going forward as of Monday.” Trump has often said unpredictability helps him negotiate.

The 5-percent tax on all Mexican goods, which would increase every month up to 25 percent under Trump's plan, would have had enormous economic implications for both countries. Americans bought 378 billion U.S. dollars worth of Mexican imports last year, led by cars and auto parts. Many members of Trump's Republican Party and business allies had urged him to reconsider — or at least postpone actually implementing the tariffs as talks continue — citing the potential harm to American consumers and manufacturers.

U.S. and Mexican officials met for more than 10 hours Friday during a third day of talks at the U.S. State Department trying to hash out a deal that would satisfy Trump's demand that Mexico dramatically increases its efforts to crack down on migrants.

The talks were said to be focused, in part, on attempting to reach a compromise on changes that would make it harder for migrants who pass through Mexico from other countries to claim asylum in the U.S., those monitoring the situation said. Mexico has opposed such a change but appeared open to considering a potential compromise that could include exceptions or waivers for different types of cases.

The joint declaration, however, makes no mention of the issue.

Trump in recent months has embraced tariffs as a political tool he can use to force countries to comply with his demands — in this case on his signature issue of immigration. And he had appeared poised earlier Friday to invoke an emergency declaration that would allow him to put the tariffs into effect if that was his final decision, according to people monitoring the talks.

“If negotiations continue to go well,” Trump “can turn that off at some point over the weekend,” Marc Short, Vice President Mike Pence's chief of staff, told reporters earlier in the day.

Talks had gotten off to a shaky start Wednesday, as the U.S. once again pressed Mexico to step up enforcement on its southern border with Guatemala and to enter into a “safe third country agreement” overhauling its asylum system. But as talks progressed Thursday, U.S. officials began to grow more optimistic, with Short reporting Mexican “receptivity” to potential asylum changes.

In Mexico, President Andrés Manuel López Obrador held out hope during his daily news conference that a deal could be reached before Monday's deadline.

Mexican Foreign Secretary Marcelo Ebrard, who said Thursday his country had agreed to deploy 6,000 National Guard troops to its border with Guatemala, tweeted the news late Friday that there would be no “tariff application on Monday.”

“Thanks to all the people who have supported us by realizing the greatness of Mexico,” he wrote.

López Obrador also tweeted. “Thanks to the support of all Mexicans, the imposition of tariffs on Mexican products exported to the USA has been avoided,” he said, calling for a gathering to celebrate in Tijuana Saturday.

Beyond Trump and several White House advisers, few in his administration had believed the tariffs were a good idea, according to officials familiar with internal deliberations. Those people had worried about the negative economic consequences for Americans and argued that tariffs — which would likely spark retaliatory taxes on U.S. exports — would also hurt the administration politically.

Republicans in Congress had also warned the White House that they were ready to stand up to the president to try to block his tariffs, which they worried would spike costs to U.S. consumers, harm the economy and imperil a major pending U.S.-Mexico-Canada trade deal.