Attorney General Jeff Sessions called Tuesday for a new focus on immigration enforcement during his first visit as the nation’s top law enforcement officer to the U.S.-Mexico border, vowing to confront the gangs and cartels plaguing the region and declaring: “This is a new era, this is the Trump era.”

Sessions met with law enforcement, members of the military and border agents in Nogales, Ariz., urging their confidence in the administration as they push to implement policies boosting agents working to secure the southern border. The tone of his comments at times echoed the explicit rhetoric President Trump himself used when discussing illegal immigration and cartels during the campaign.

“When we talk about MS-13 and the cartels, what do we mean? We mean international criminal organizations that turn cities and suburbs into warzones, that rape and kill innocent civilians, and who profit by smuggling poison and other human beings across our borders,” Sessions said.

“… It is here on this very sliver of land—on this border—that we take our stand. It is a direct threat to our legal system, peace and prosperity,” he said.

Timed with his visit, Sessions issued a memo to all U.S. attorneys asking federal prosecutors to renew focus on immigration enforcement. He asked them to focus on particular offenses that can help prevent and deter illegal immigration – and to each, designate a border security coordinator to oversee such efforts.

Sessions’ visit comes amid new questions over the future of Trump’s promised border wall. Secretary of State Rex Tillerson has suggested the wall is not a “leading priority,” and Homeland Security Secretary John Kelly told lawmakers last week that the administration would not build a wall from “sea to shining sea.”

But Sessions stressed enforcement as he met border agents and toured the area known as the Tuscon Sector.

The Tuscon Sector, which covers most of Arizona, once was considered one of the most congested areas in illegal border crossings and drug smuggling. But in recent years, that reputation has shifted to the Rio Grande Valley in Texas.

Last year, the Arizona area saw about 65,000 arrests—that’s roughly half the number of arrests agents made in 2012, according to Border Patrol data. Marijuana arrests also have dropped in the area by about 28 percent, from 1 million pounds in 2012 to 728,000 last year.

“We hear you, and we have your back,” Sessions said Tuesday. “We will secure this border and bring the full weight of both the immigration courts and federal criminal enforcement to combat this attack on our national security and sovereignty.”

Sessions cited an “unprecedented” 40 percent drop in illegal crossings in January and February of this year – adding that March had the lowest monthly figure for “at least 17 years.”

In his memo, Sessions added that U.S. attorneys should make the prosecution of assault on a federal law enforcement officer a “top priority.”

“If someone dares to assault one of our folks in the line of duty, they will do federal time for it,” Sessions said.

Sessions also announced that the department would add 50 immigration judges to the bench this year, and an additional 75 judges in 2018.

"The catch and release policies of the past are over," he said.

Fox News' Matthew Dean contributed to this report.