WASHINGTON — Senate Democrats and House Republicans are moving separately to slash President Barack Obama’s $3.7 billion emergency spending request for the border, but they’re unlikely to end up with a deal that could pass both chambers.

Senate Appropriations Chairwoman Barbara Mikulski planned to unveil legislation Wednesday allocating $2.7 billion for more immigration judges, detention facilities and other resources on the South Texas border, where tens of thousands of unaccompanied minors have been arriving from Central America.

That amounts to a $1 billion reduction from Obama’s request. But House Republicans were expected to go even further, with more limited spending that would be focused more heavily on enforcement provisions, including National Guard troops, than on caring for the youths. House Republicans were to discuss their legislation Wednesday and hear from a border task force appointed by Speaker John Boehner, R-Ohio.

Most problematically, Mikulski, D-Md., said she was omitting from her legislation any changes to a 2008 trafficking victims law that critics say has contributed to the crisis by allowing Central American youths to stay in this country indefinitely while awaiting far-off court dates. Republicans are demanding changes in that law as the price for approving any money for the crisis and have said that will be an important part of their legislation in the House.

“I don’t believe the American people will support sending more money to the border unless both parties work together to address these policies and actually solve this problem,” Boehner said.