More than 310,000 illegal immigrants were apprehended nationwide in 2017, 98 percent of whom were apprehended at the southern border, according to new data released Tuesday by the Department of Homeland Security (DHS) detailing America's immigration control efforts over the past year.

The overwhelming majority of those immigrants were from Mexico or Central America, the report showed: 162,891 were from El Salvador, Guatemala, and Honduras, and another 127,938 were from Mexico. Around 10 percent of apprehended immigrants had previously been apprehended in FY 2017.

The overall number of apprehensions represents a 24-percent decline over 2016, providing further evidence for a drop off in attempted illegal immigration following the election of President Donald Trump. Indeed, 2017 marked the lowest level of illegal border crossing since CBP was set up in 2003.

However, the number of apprehensions highlights the urgency of implementing Trump's immigration priorities, including constructing a wall on the southern border, according to DHS.

"We have clearly seen the successful results of the President's commitment to supporting the frontline officers and agents of DHS as they enforce the law and secure our borders," said Acting Secretary of Homeland Security Elaine Duke. "We have an obligation to uphold the integrity of our immigration system, but we must do more to step up and close loopholes to protect the American worker, our economy, and our communities."

In addition to the border apprehensions by the Customs and Border Protection (CBP) agency, the Immigration and Customs Enforcement (ICE) agency reported 143,470 arrests and 226,119 removals. Those arrests focus overwhelmingly on undocumented individuals whom ICE identified as engaging in some specific criminal behavior: having a criminal conviction or a pending criminal charge, being an ICE fugitive, or being an illegal re-entrant.

In sum, CBP officers and border patrol agents arrested 20,131 criminal aliens, as well as an additional 10,908 individuals wanted by law enforcement.

Tom Homan, acting director of ICE, insisted that a more aggressive policy response was needed to support ICE’s public safety mission.

"We need to confront and address misguided policies and loopholes that only serve as a pull factor for illegal immigration. We must continue to target violent gangs like MS-13, and prevent them from rebuilding what we have begun to dismantle. Finally, we need to find a solution to the dangerous sanctuary city policies and the politicians who needlessly risk innocent lives to protect criminals who are illegally present in the United States," Homan said.

Transnational gangs and drug trafficking have both been major focuses of U.S. immigration enforcement agencies. ICE Homeland Security Investigations (HSI) arrested 796 members of the gang MS-13, 83 percent more than last year. That figure is included in the 4,818 criminal arrests of gang members; ICE Enforcement and Removal Operations also administratively arrested 5,225 gang members.

CBP also seized substantial quantities of illegal drugs intended to be smuggled into the United States. It reported seizing 1.59 million pounds of marijuana; 273,580 pounds cocaine; 66,617 pounds of methamphetamine; 5,760 pounds of heroin; and 1,485 pounds of fentanyl.

The amount of seized fentanyl is particularly noteworthy, given that just four years ago, CBP reported a total seizure of 2 pounds, an enormous increase in the drug responsible for the most drug overdose deaths in 2016.

"We are… concerned about the significant uptick in the smuggling of opioids and other hard narcotics, including heroin and cocaine, which generally increase when illegal border crossings spike," said Acting Deputy CBP Commissioner Ron Vitiello. "The men and women of CBP, working along our borders and at the ports of entry protecting our great nation, are doing outstanding work. For us to truly have an operationally secure border, we must close loopholes in our laws that help fund the cartels."