U.S. Customs and Border Patrol agents detained almost a million individuals crossing the southwestern border with Mexico during the last year, according to government data released Tuesday.

CBP officers detained 977,509 individuals between October 2018 and September 2019. The immigration enforcement agency stopped 512,090 people from crossing into the United States from Mexico during the previous fiscal year - marking an 88 percent increase.

The numbers dropped dramatically from May until September, perhaps a byproduct on the Trump administration's threat to impose tariffs on goods imported from Mexico and the Mexican government's stepped up role in policing its side of the 1,954-mile border.

CBP reported 132,856 unlawful entry arrests in May and just 40,507 by the end of September.

Border Patrol agents also stopped 126,001 individuals, who were deemed inadmissible over the budget year that ended Sept. 30.

The decline of unauthorized border crossings over the past few months and news of custody deaths and teeming facilities full of children and families has faded from front pages and talking points of politicians.

However, immigration officials argue that the number of migrants coming over border is still high, and that resources to combat the mass flow of migrants are still stretched.

U.S. Customs and Border Patrol agents detained almost one million individuals crossing the southwestern border with Mexico during the last year, according to government data released Tuesday. Pictured above is a family of two from Central America surrendering to CBP officers in December 2018 after crossing the Tijuana-U.S. border

U.S. Customs and Border Patrol announced Tuesday it detained 977,509 individuals along the southwestern border with Mexico between October 2018 and September 2019. Pictured above is a CBP agent near the Mexico-Texas border region

U.S. Customs and Border Patrol agents detained 977,509 individuals along the southwestern border with Mexico between October 2018 and September 2019, an increase of over 400,000 compared to the fiscal year that covered October 2017 to September 2018

'It is kind of a new norm. We're at risk at any time,' said Brian Hastings, chief of law enforcement operations at Border Patrol said in an interview with The Associated Press.

'We will go back, mark the words, we will go back to the crisis level that we had before.'

According to the CBP, 'apprehensions refers to the physical control or temporary detainment of a person who is not lawfully in the U.S. which may or may not result in an arrest.'

Inadmissible are 'individuals encountered at ports of entry who are seeking lawful admission into the United States but are determined to be inadmissible, individuals presenting themselves to seek humanitarian protection under our laws, and individuals who withdraw an application for admission and return to their countries of origin within a short time frame.'

Immigration has been a top issue since President Donald Trump took office almost three years ago, with Democrats heavily critical of his administration on border conditions.

But Washington is now dominated by talk of impeachment and immigration seems somewhat less pressing, with monthly apprehension numbers declining and Mexico and other nations enhancing cooperation with the U.S. on immigration issues.

Still, Trump has not forgotten an issue that was key to his 2016 victory, pointing to it often at public events and at rallies. And as he ramps up his campaign heading into 2020, he's likely to invoke it often as a measure of his success, telling his supporters that construction is happening on the long-stalled wall he promised along the southern border and that far fewer people are being apprehended crossing the border illegally - if current numbers hold, that is.

A CBP report released Tuesday revealed that immigration agents stopped 126,001 who were deemed inadmissible from October 2018 to September 2019. Pictured above are migrants waiting on the Mexican side of the border awaiting for their asylum hearings

CBP reported 132,856 unlawful entry arrests in May and just 40,507 by the end of September. Three migrants (pictured in July 2019) managed to evade the Mexican National Guard and cross the Rio Grande onto U.S. territory

A one-year-old Mexican girl sits on the Gateway International Bridge during migrant protests in early October. As part of the Trump administration's asylum policy, people seeking refuge in the United States have to wait in Mexico before meeting an immigration judge in the U.S.

There were nearly 1 million crossings from the early 2000s, but those were mostly single men from Mexico who were easily returned, not families from Central America who require much more care.

While the numbers surged, Homeland Security agents and officers were overwhelmed by the number of families crossing the border as the numbers continued to rise. Families with small children require much more care.

Border officers pleaded for help but it wasn't until over the summer, when reports of squalid conditions and surging numbers of detainees and children dying were published that Congress authorized additional funding to increase capacity. That funding expired at the end of the fiscal year.

There were more than 200 large groups of more than 100 migrants dropped off by smugglers in remote areas - something that can shut down an entire station for the day for processing - and there were at least 140,000 people who evaded capture.

Previously, 2014 was considered a crisis year, when the Obama administration saw a crush of unaccompanied children at the border. The overall apprehensions by Border Patrol were 479,371 - there were 372,000 more in 2019.

Border agents saw more families crossing the border in the month of May this year than the entire budget year of 2014. In 2014, there were about 68,000 families for the entire budget year compared to 84,000 in May 2019 alone.

Border Patrol agents guard a fence during Tuesday's press conference which revealed U.S. Customs and Border Patrol agents detained 977,509 individuals along the southwestern border with Mexico between October 2018 and September 2019

Migrants greet their Mexican families through the border wall during the Hugs Not Walls event organized by the Border Network for Human Rights in Chihuahua, Mexico, on Saturday

There were more than 4,900 people rescued including a dramatic increase in river rescues - 742 from 86 the year before.

'I am incredibly proud of the agents,' Hastings said. 'They have been vilified, but they deserve to be thanked because we have never, ever dealt with anything like this before.'

Members of the Border Patrol, Texas Department of Public Safety, Air and Marine Operations, and the DHS Volunteer Force from Office of Field Operations saved 110 migrants from extreme temperatures at a ranch land in Freer, Texas, in June

CBP officers detained 977,509 individuals between October 2018 and September 2019. The immigration enforcement agency stopped 512,090 people from crossing into the United States from Mexico during the previous fiscal year - marking an 88 percent increase. Pictured above is a group of Central American migrants who were rescued at a ranch in Texas in June

Hastings said the so-called Remain in Mexico program that is expanding in parts of California and Texas, plus a new rule barring asylum to those who pass through a third country, and crackdowns by Mexico at its own southern border have helped. More than 55,000 people have been turned back , and officials say many have gone home.

The program won't be extended into the Arizona border right now, Hastings said, because officials are focused on increasing the number of people returned in the areas where it is already in place. And he's seen Mexico crack down before, but 'we've never seen them sustain for that long.'

Still, Hastings has said the number of immigration officials reassigned to the border has gone down, as more agents and officers go back to their regular jobs.

The Border Patrol is looking to create a civilian workforce to help agents with some non-law enforcement duties, he said.