The Border Patrol union slammed the execution of the National Guard deployment to the southern border on Friday, saying that resources were being wasted and that troops were not being used as "initially planned".

"Someone in between President Trump and the folks on the border is not relaying the information correctly," Art Del Cueto, the national spokesperson for the National Border Patrol Council (NBPC) told ABC News.

In an interview with The Los Angeles Times on Thursday, union president Brandon Judd harshly criticized the deployment of National Guard troops as "a colossal waste of resources" and of "no benefit."

Judd told the Los Angeles Times that when he found out the National Guard was going to the border he was "extremely excited because previous deployments on the border helped alleviate the Border Patrol's workload.

But this time, he told the paper, "that has not happened at all."

The union, which represents around 18,000 agents and support personnel, had hoped troops would be used in similar capacities as past deployments to the border and that they would provide support as the "eyes and ears" for Border Patrol, according to its spokesperson.

"We're not attacking President Trump. It's not his fault, but the people underneath him aren't understanding what he wants," said Del Cuento who added that he hasn't seen evidence that deploying the National Guard has helped the Border Patrol reallocate its workload to the frontlines.

The union endorsed Trump's candidacy and have been staunch supporters of the president.

Border Patrol Chief and acting deputy commissioner Ronald Vitiello defended his agency on Friday against criticism, saying "we’ve already seen dividends from it."

"The categorization that it's wasteful or it's not effective, it's not resonating with me," Vitiello said.

Vitiello said he doesn't think the union realizes that the differences are "based on the lessons learned” from previous deployments.

This comes less than two months after the Trump administration announced that it was deploying troops to the U.S.-Mexico border with the goal of gaining "operational control" of the border.

The exact goals and timeframe for the deployment are unclear.

President Trump has said he wants National Guardsmen to guard the U.S. border with Mexico until a border wall is built. Border Patrol has said the length of the deployment will be "conditions-based" and depend on the amount of funding available.

In 2006 the Bush administration deployed 6,000 guardsmen as part of the border support mission known as Operation Jump Start.

President Barack Obama deployed 1,200 guardsmen in 2010 as part of a similar mission called Operation Phalanx.

The current mission on the border is designed to free-up Border Patrol agents to carry out arrests and interdictions, according to the Department of Homeland Security (DHS), which oversees Border Patrol.

National Guard soldiers are not allowed to perform any federal, state, local or tribal law enforcement functions and have been assigned to duties that don't require they be armed.

"We’ve already seen dividends from it," said Vitiello.

He credited about 4,000 arrests and the confiscation of 4,000 pounds of marijuana with direct troop support.

"The Guardsmen have been great partners for us and we’re grateful that they are out there with us," said Vitiello.

As of Friday, there were just over 1,000 on-the-ground troops dedicated to supporting Border Patrol, plus 500 to 600 additional troops to provide logistics and other support, according to Vitiello.

The current on-the-ground missions include air interdiction support, road maintenance and vegetation clearing, operational support with radio operators, fleet maintenance, intelligence analysts and surveillance support.

Defense Secretary Jim Mattis has authorized up to 4,000 total troops to participate through the end of September.

The Department of Defense had no comment on criticism from the union.

Elizabeth Mclaughlin and Luis Martinez contributed to this story.