President Donald Trump continued his personal war against Mexico over the issue of Latin American immigrants, this time threatening to impose a hefty 25 percent tariffs on cars imported from Mexico to stop immigrant traffic into the United States.

Trump is demanding that Mexico, the country he couldn't force to pay for his border wall, do more to stop illegal migrants and drug trafficking. Trump last week threatened to immediately shut the border with Mexico to cut the flow of Immigrants but backed down in the face of intense pressure from Democrats and his own Republican Party.

Trump then issued a revised threat, saying he'll give Mexico "a one-year warning" to stop drug trafficking or face tariffs.

"Before we close the border we'll put the tariffs on the cars," he said. "I don't think we'll ever have to close the border because the penalty of tariffs on cars coming into the United States from Mexico at 25 percent will be massive."

Trump rash pronouncement to close the border with Mexico, which he made without consulting anyone else, triggered panic among business leaders last weekend when he made the threat.

The U.S. Chamber of Commerce welcomed Trump's decision not to close the border with Mexico but said Congress has to do more.

"Congress should also ensure Customs and Border Protection officials receive the resources they need to reduce the excessive wait times affecting legitimate trade and travel across the border," said Neil Bradley, a top official with the Chamber in a statement.

U.S. border officials have estimated that some 100,000 migrants were arrested or encountered at the border in March, the highest number in a decade. Most of these unfortunates are Central American families mainly from Guatemala, El Salvador, and Honduras seeking asylum to escape poverty and rising deadly violence at home.

A much-criticized decision is taken by the Department of Homeland Security, which transferred 750 border agents from commercial to immigration duties. This move resulted in long delays for cross-border trade.

Mexican exporters now plan to send their goods to the United States by air to avoid an 8 km long line of trucks at the border caused by the Trump administration reassigning federal agents to immigration duties from customs checks.

Mexican Economy Minister Graciela Marquez Colin rebutted Trump's threat and said the issue of illegal immigration shouldn't harm the two countries' trade relationship.

"For the Mexican government, it is very important to keep migration issues and trade issues separate," said Colin.