CALEXICO, Calif. (Reuters) - President Donald Trump on Friday promised approximately 450 miles (725 km) of new “wall” along the southern U.S. border, after threatening to slap Mexico with an unspecified economic penalty to crack down on what he describes as a crisis of undocumented immigration and drug trafficking.

Referring to a “colossal surge” of immigrants, Trump convened a discussion with immigration officials and local leaders in Calexico on the U.S.-Mexico border just north of the much larger city of Mexicali.

Before touring a just completed 30-foot (9 meter) tall, 2.2 mile (3.5 km) barrier at Calexico, Trump said more U.S. military resources will be dispatched to the border.

“Our country is full,” Trump said in a warning to migrants. “Can’t take you anymore.

The Republican president’s latest pronouncements, including a threat to impose auto tariffs on Mexico, are in response to a rising number of migrants, many of them families with children, traveling northward from Central America through Mexico and to the U.S. border.

During Friday’s discussion in Calexico, Trump was handed a diamond-shaped piece of steel slate - the material used to construct barriers along the border.

Lt. Gen. Todd Semonite of the U.S. Army Corps of Engineers said that by the end of next year - just after the November 2020 presidential election - about 450 miles (725 km) of new barrier will be completed. Border officials have said they need 722 miles (1,162 km) of new or replacement barriers.

Trump is counting on seizing funds from other federal accounts and shifting them for the construction, a move being challenged in federal court because Congress has not given approval. Democrats generally oppose Trump’s wall proposal, suggesting instead other types of enhanced border security that they argue would be more effective and less costly.

Hammering on a favorite theme, Trump earlier on Friday said he was considering imposing an unspecified economic penalty on Mexico unless it helps alleviate the United States’ drug and immigrant flows.

U.S. President Donald Trump talks to reporters as he departs for travel to the U.S.-Mexico border from the White House in Washington, U.S., April 5, 2019. REUTERS/Carlos Barria

Although Trump has several times linked the issues of illegal immigration and drug smuggling as he tries to tighten border security, much of the drug trade is not carried out by migrants but by professional crime gangs that send narcotics to the United States in vehicles through official ports of entry.

Praising Mexico for moving recently against drug traffickers, Trump said, “If they continue that, everything will be fine. If they don’t we’re going to tariff their cars at 25 percent.”

“Also, I’m looking at an economic penalty for all of the drugs that are coming in through the southern border and killing our people,” Trump told reporters in Washington before departing for southern California.

TRUMP THREATS

Trump said the drug-related tariff would supplant provisions of a trade deal, the U.S.-Mexico-Canada Agreement, known as USMCA, which has not been approved by Congress.

In a Twitter post on Friday morning, Trump repeated a threat to close the border if Mexico “stops apprehending and bringing the illegals back to where they came from...”

“I am looking at an economic penalty for the 500 Billion Dollars in illegal DRUGS that are shipped and smuggled through Mexico and across our Southern Border. Over 100,00 Americans die each year, sooo many families destroyed!” the president tweeted.

It was not immediately clear what other penalties he was considering. The White House did not respond to a request for elaboration.

It also was unclear where Trump got the $500 billion figure.

Mike Vigil, a former chief of international operations for the U.S. Drug Enforcement Administration, said the amount of drugs smuggled into the United States annually was probably in the range of $50-$60 billion. He emphasized that it was fueled by U.S. demand.

“He’s blaming Mexico for our drug problem,” Vigil said, adding that his words could hurt bilateral cooperation in battling drug-trafficking. “The president should focus on reducing the demand and facilitating drug treatment centers here in the United States,” he added.

In recent days, Mexico has taken a more rigorous approach to interviewing and registering immigrants from Central America, Haiti and Cuba, according to officials.

Previously, the Mexican government freely handed out humanitarian visas with the goal of allowing people to stay and work legally in Mexico. But it backed away from that policy after a surge in those requesting the documents and amid criticism from Washington.

On Thursday, a Mexican federal police plane flew dozens of Haitians home.

On Friday, the Migration Institute said on Twitter that 57 Cubans were sent back to Cuba by plane in the morning. More than 60 Cubans were flown home last week.

Meanwhile, 20 states have filed a motion to block Trump’s attempts to divert federal funds through an emergency declaration, New York Attorney General Letitia James, a Democrat, said on Friday. The U.S. House of Representatives on Friday also filed a lawsuit challenging Trump’s ability to seize the funds, House Speaker Nancy Pelosi, also a Democrat, said.