The State Department announced Monday it will cut new foreign aid to the "Northern Triangle" countries -- Guatemala, Honduras, and El Salvador -- unless their governments take "concrete action" to stem the flow of migrants towards the United States.

The aggressive move came less than two weeks after the Trump administration reached a last-minute deal with Mexico, which called for the country's deployment of more troops to its own southern border and tighter asylum protocols. The U.S. and Mexico reached the accord shortly before the White House was set to impose a series of escalating tariffs on its southern neighbor.

President Trump previously pushed in March to cut $615 million in aid to the Northern Triangle, noting that the nations have been home to some of the migrant caravans that have marched through Mexico to the U.S. border to claim asylum, in some cases fraudulently.

On further review, the State Department said the administration has decided to continue to provide $432 million for anti-gang, education, and health initiatives. U.S. officials said the review looked at roughly 700 projects funded with fiscal 2017 money by the United States in the three countries and concluded that a significant number were too far advanced to end them.

MEXICO VOWS TO HELP CENTRAL AMERICAN MIGRANTS AMID CRACKDOWN

However, the latest plans showed roughly $370 million from the fiscal year 2018 budget will no longer be spent on the Northern Triangle and approximately $185 million in funding from the 2017 budget will be withheld, at least for now.

A State Department official told Fox News a re-evaluation would be concluded no later than April 2020.

"We will not provide new funds for programs in those countries until we are satisfied that the Northern Triangle governments are taking concrete actions to reduce the number of migrants coming to the U.S. border," State Department spokeswoman Morgan Ortagus said. "This is consistent with the president’s direction and with the recognition that it is critical that there be sufficient political will in these countries to address the problem at its source."

She added, "Working with Congress, we will reprogram those funds to other priorities as appropriate."

Ortagus noted that "previously awarded grants and contracts will continue with current funding."

Many Democrats called the decision callous and unproductive.

"As feared, a presidential tantrum will limit our nation’s ability to actually help address the challenges forcing people to flee to the U.S.," Sen. Bob Menendez, D-N.J., tweeted.

The Northern Triangle's immigration policies have long rankled the Trump administration. Last December, the U.S. pledged more than $10 billion in aid to Central America and Mexico to help keep migrants put. Later that month, Trump tweeted: "...Honduras, Guatemala and El Salvador are doing nothing for the United States but taking our money.

"Word is that a new Caravan is forming in Honduras and they are doing nothing about it," Trump added. "We will be cutting off all aid to these 3 countries -- taking advantage of U.S. for years!"

The State Department in March then notified Congress that it would look to suspend 2017 and 2018 payments to the trio of nations.

Meanwhile, Mexico has offered refuge to migrants with credible fears as thousands remain in the country while they await court dates for asylum petitions in the U.S. The understaffed and underfunded Mexican refugee commission has faced a backlog of cases.

But, in recent months, police and immigration have stepped up enforcement in southern Mexico, setting up highway checkpoints, raiding a caravan of mostly Central American migrants and trying to keep people off the northbound train known as "the beast."

At the same time, Mexicans have grown increasingly intolerant of the large numbers of migrants passing through their country in an attempt to reach the United States.

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A June poll in Mexican newspaper El Universal showed that Mexicans are less receptive to allowing undocumented migrants to come in, or to stay on permanently as refugees, than they were in October, when caravans with thousands of Central American migrants were winding their way north.

Fox News' Rich Edson and The Associated Press contributed to this report.