Conservative opposition remains but negotiators worked through the weekend on the details. The Zika money has stalled since Obama first requested $1.9 billion in February, but congressional Republican leaders seem likely to jettison provisions opposed by Democrats restricting any of the money from going to affiliates of Planned Parenthood in Puerto Rico.

It comes as government scientists step up their warnings about the spread of the virus, which can cause devastating birth defects. More than 670 pregnant women in the states and Washington, D.C., have the virus, leading to the birth of at least 17 babies with microcephaly so far.

On Friday, Centers for Disease Control and Prevention Director Thomas Frieden said that "we are now essentially out of money" and warned that the country is "about to see a bunch of kids born with microcephaly" in the coming months.

Obama, just back from a trip to Asia, invited the GOP leaders, House Speaker Paul Ryan and Senate Majority Leader Mitch McConnell, and their counterparts, House Democratic leader Nancy Pelosi and Senate Democratic leader Harry Reid.

The lawmakers have been back from a seven-week summer recess for only a week but already are eager to depart again so that vulnerable lawmakers of both parties can campaign for re-election. The government funding bill is the only must-pass piece of legislation ahead of the election and thus has become the vehicle for the Zika provisions.

Obama's priorities for a lame-duck post-election session of Congress may also be on the table at the White House Monday afternoon. Chief among these is Obama's one major remaining foreign policy priority, the 12-nation Asia free-trade deal Trans-Pacific Partnership. During his recent trip to Asia, Obama repeatedly called on Congress to pass what the White House considers a legacy-burnishing deal.

Despite longstanding support for free trade among Capitol Hill Republicans, including Ryan and McConnell, there is now bipartisan opposition to the deal in Congress and on the presidential campaign trail, where Donald Trump has railed against it and Democrat Hillary Clinton reversed herself under pressure from the Democratic base and now opposes it.

Ryan has offered assurances to rank-and-file GOP lawmakers that the TPP deal will not move in the lame-duck session, and McConnell has also indicated chances are slim in the Senate.