Congress has only a few days left before August recess to approve President Obama’s request for an additional $3.7 billion for the border crisis, with no scheduled voting dates and little apparent optimism for passage.

The House and Senate Appropriations committees, where the first key votes will take place, each said Monday that no date has been set.

The Republican-led House is expected to pose the biggest hurdle for the president’s emergency-spending request, amid tens of thousands of children and others from Central America attempting to cross the southwestern U.S. border in recent months.

Kentucky GOP Rep. Hal Rogers, chairman of the lower chamber’s appropriations committee, has already said Obama is asking for “too much” and that non-emergency needs are either covered in fiscal 2015 spending bills or could be handled through Congress’ routine appropriations process.

Rogers also has indicated his committee is trying to “pull together” an emergency package, but details have yet to emerge.

House Speaker John Boehner last week said he didn’t have “as much optimism as I’d like to have” about passing an emergency plan before the recess to deal with the border crisis.

The House has eight working days remaining before the break begins August 1.

In the Democrat-controlled Senate, Maryland Sen. Barbara Mikulski, chairman of that chamber’s appropriations committee, said she plans to release her draft of the supplemental spending bill Wednesday. However, she did not give a dollar figure.

"We're going to try to get it done (before the August recess)," she said.

Mikulski has -- like Obama and most other Capitol Hill lawmakers --framed the request in terms of a “humanitarian” need or crisis, with Democrats and Republicans essentially arguing that efforts to amend the White House request is tantamount to holding the children hostage.

“The crisis actually begins in Central America where brutal, violent gangs … are trying to recruit boys into organized crime, drug smuggling and human trafficking and girls into human trafficking and other just dangerous and repugnant circumstances,” Mikulski said  last week. “I hope that in passing the appropriations. … We need to meet these urgent humanitarian needs.”

Senate Majority Leader Harry Reid suggested last week that GOP-led concerns about border security are exaggerated and said “radical Republicans would rather hold these kids ransom,” than consider reasonable solutions.

On Sunday, Texas GOP Sen. Ted Cruz said that the way to help the children is to "eliminate the magnet,” which is Obama's 2012 executive memo that makes some young illegal immigrants eligible for deferred deportation.

Should Congress fail to pass the request before recess, members could avoid the issue until after the November mid-terms, with both parties making failed passage an election issue on which to blame the other.

Beyond the spending amount, the bill also could get held up by a 2008 law that allows children from non-bordering countries to enter the United States legally.

The law was intended to help victims of human trafficking but appears to be contributing to the current crisis by ensuring court hearings for the children now arriving from Central America.

In practice, the process often allows the children to stay in the United States for years as their cases wend their way through the badly backlogged immigration court system. And oftentimes they never show up for their court dates.

Obama administration officials along with Republican lawmakers want to change the law so that Central American children can be treated the same way as Mexican minors, who can be turned around quickly by Border Patrol agents.

But Democrats and advocacy groups say such a change would put the kids in jeopardy.

“We will oppose this link even if it means the funding bill goes down,” said Kevin Appleby, director of migration and refugee policy for the U.S. Conference of Catholic Bishops. If the changes go through, “They’ll be sent back to their persecutors with no help whatsoever, and possibly to their deaths.”

The Associated Press contributed to this report.