A number of top congressional Republicans claim that the Obama administration is failing to address the main reason why unaccompanied child migrants are flooding into the United States at unprecedented levels.

President Obama laid out a plan Tuesday while requesting $3.7 billion from Congress in emergency appropriations to stem the wave of child migrants coming into the U.S. from Honduras, Guatemala and El Salvador.

Nearly 40,000 minors have crossed into the U.S. this year from Honduras, El Salvador and Guatemala, according to The Christian Science Monitor.

The extra funds, which are not covered in this year's budget, will improve border security, provide better housing and care for the children, speed up the judicial process for the children's' cases and help the children's countries of origin repatriate them once they get deported.

However, some top Republicans believe Obama is failing to address the main issue.

Republicans cite a 2008 child trafficking law that speeds up the process for immigrants from Canada and Mexico more quickly than immigrants who come to the U.S. illegally from other countries. Republicans believe that the law minimizes the deportation of migrant children from Central American countries, thereby encouraging more to come to the U.S.

While Obama announced that he would seek reforms to the law last week, his proposal on Tuesday did not mention any changes to the 2008 bill.

Senate Minority Whip John Cornyn (R-Tex.) accused Obama of asking Congress for a "blank check" while also trying to "peel off" changing the 2008 legislation.

"He just decided not to do that because of the push back that he got from some [in] his own political base," Cornyn told reporters Tuesday, according to the Christian Science Monitor.

However, Democrats see the 2008 law as providing protections for minors.

"While I support the president asking for more money, I am deeply concerned that the legal rights of children fleeing violence that are part of our current law may get curtailed," Rep. Luis Gutiérrez (D) of Illinois said in a statement, according to CSM.

The law, which was passed by President George W. Bush, details how the issue of children crossing the border should be handled. According to the law, border patrol agents are allowed to decide whether or not a minor can stay in the U.S. when the children are from countries close to the U.S. The process is expedited so the children can be quickly and safely transported back to their countries of origin.

The law requires that children who came to the U.S. from a farther distance be taken to the Department of Health and Human Services within 72 hours of being apprehended. The agency then finds them a safe place to stay, as well as legal counsel. However, they can wait one to two years for their cases to be heard due to a backlog in immigration courts. Therefore, many people from Central America have been able to stay in the U.S. longer.

Officials from the White House said they will request that Congress make adjustments to the law so children from "non-contiguous" countries are treated similarly as those from contiguous countries.

Randy Capps, director of research for U.S. programs at the Migration Policy Institute, a nonpartisan think tank, said changing the law while ensuring safeties for undocumented children will not be easy.

"These children in a lot of cases have been through a lot of terrible things, and differentiating which rise to the level of asylum claims and trafficking claims are not always that easy," he said, according to CSM.

Capps said that implementing reforms will be difficult, as the President is facing border enforcement pressure from Republicans, while Democrats are concerned about the welfare of unaccompanied minors.