Immigration and Customs Enforcement has released more than 160,000 migrants who crossed illegally into the U.S. since December 2018 – and most of those people aren't showing up for their dates in immigration court, according to a senior ICE official.

In an effort to respond to the increasing surge of migrants a the Southern U.S. border – 109,144 were apprehended in April alone – the Department of Justice had its immigration court system establish a pilot program that created expedited court proceedings in 10 cities along the border.

However, 87.5 percent of the immigrants facing orders of removal in those courts failed to appear before a judge.

'There are often no consequences for those who fail to depart as ordered,' said Nathalie R. Asher, the acting executive associate director of enforcement and removal operations at ICE.

This graph shows the increase in immigrants coming across the Southern U.S. border, including those who cross illegally and those who present themselves at legal checkpoints. Each line represents the first seven months of a different fiscal year, with 2019 already seeing a sharp uptick

'As a result of these issues, of the family units from Central America who were apprehended at the southern border in fiscal year 2017, more than 98 percent remain in the country today,' Asher said Wednesday before the U.S. Senate subcommittee on Border Security and Immigration.

Asher provided the numbers during a hearing in which officials sought more funding from Congress – as well as major changes to current immigration law – to address what she described as a 'humanitarian and security crisis.'

'Very few members of family units will be removed; the push and full factors that incentivize families to make the dangerous journey in this country must be addressed,' Asher said.

ICE wants the authority to detain migrant children for long periods of time, and the ability to immediately deport unaccompanied minors to their home country. They also want to make it harder for migrants to pursue asylum in the U.S.

Complicating the issue is a massive backlog of more than 900,000 cases in U.S. immigration courts.

Nathalie Asher, acting executive associate director for enforcement and removal operations for the Department of Homeland Security, testifies during the Senate Judiciary Committee's Border Security and Immigration Subcommittee hearing in Washington DC on May 8, 2019

Asher's statements came the same day that the Department of Homeland Security released the latest border apprehension numbers, with nearly 110,000 encountered in April, including 58,000 families and 8,800 unaccompanied children taken into custody – an 87 percent increase in monthly arrivals compared to January.

Border Patrol Chief Carla Provost told senators on Wednesday that apprehension numbers were 'off the charts,' and she's had to divert agents to care for children.

'They (immigrants) have received the message loud and clear: Bring a child, you will be released,' she said.

Provost said shifting resources will not address the crisis. She said she is worried about drugs and other contraband that is getting through as resources are shifted to caring for children.

The issue is also about people posing fraudulently as families – using children who aren't related to them – in an effort to be released immediately into the U.S.

From October 2017 – February 2018, officials found a 315 percent increase 'in the number of cases of adults with minors fraudulently posing as 'family units' to gain entry' to the U.S., according to DHS.

'Cases of fake families are popping up everywhere. And children are being used as pawns,' former Homeland Security Secretary Kirstjen Nielsen said in a speech last month.

She added that DHS had discovered 'child recycling rings,' in which the same children are used over and over again in an attempts to get more migrants released in the US.

Central American migrants walk during their journey towards the United States, in Villa Comaltitlan, Mexico April 18, 2019

The increase flow of migrants across the border has forced the Trump administration to release some people immediately after they arrive – without processing them through ICE.

Trump has pledged to end such a 'catch-and-release' policy, but has so far been stymied by the sheer volume of migrants flowing across the border.

Further complicating things is the fact that the government can't legally detain migrant children for more than 20 days, which has led to more of those families being released since Trump ended the administration's policy of separating children from parents last June.

The increased flow of migrants at the border has been driven largely by people fleeing gang violence, poverty and corruption in the Northern Triangle region of Central America – Guatemala, Honduras and El Salvador.

Most have sought asylum in the U.S., saying they would face threats of violence and death if they returned to their home countries.

The process for seeking asylum often last years and many are ultimately unsuccessful. Some immigrants are allowed to live in the U.S. while awaiting their fate in court while others spend the time in detention centers.