The House and Senate appear to be at odds over who goes first on the supplemental, as both plan their schedule through the Memorial Day recess.
House Majority Leader Rep. Steny Hoyer, D-Md., Tuesday said he intends to bring the emergency war supplemental to the floor before the Memorial Day break, but added that House Democratic leaders would prefer that the Senate move the bill first.
"We would certainly like to have them move the supplemental and send it over to us and we'll take it up," Hoyer told reporters. "We think that is the more predictive of what can be done in the Senate."
He added "it will save some time if the Senate does it first, so we know we don't have to go back and forth on it."
A Hoyer spokeswoman said his comments did not preclude a markup in the House Appropriations Committee.
Pentagon officials have called on Congress to pass the measure -- which includes $37.5 billion for Iraq and Afghanistan for the remainder of fiscal 2010 -- by Memorial Day.
Senate Appropriations Committee Chairman Daniel Inouye, D-Hawaii, said Tuesday Senate Democratic leaders will make a decision soon on when to mark up the supplemental, which could take place as soon as Thursday.
But earlier Tuesday, Senate Majority Leader Harry Reid, D-Nev., declined to endorse Hoyer's plan, noting that he has not made a decision yet about the timing of the supplemental.
If the Senate does go first, it could use a $5.1 billion emergency supplemental spending package for Federal Emergency Management Agency disaster relief and a youth jobs initiatives passed by the House in March as a legislative vehicle.
A Democratic leadership aide said Senate Democrats hope to take up tax extenders legislation next week after finishing a financial regulatory reform bill Monday or Tuesday. The Senate plan would be for the House to pass the supplemental first, and then for the Senate to move it in the final week before Memorial Day recess.
Senate Appropriations Committee ranking member Thad Cochran, R-Miss., said the measure could include aid to the Gulf Coast in response to a massive oil spill in the Gulf of Mexico triggered by a rig explosion April 20.
"There could be" Gulf aid in the package, Cochran said. "I know there have been requests for us to make available specific funds. Right now, there are a lot of unknowns about what the cost will be and when the money will be needed. Obviously, something will be needed at some point to deal with the situation and we will try to be responsive."
Dan Friedman and Megan Scully contributed to this report.