WASHINGTON (AP) — Congressional Democrats are preparing a plan that would boost President Joe Biden's requested $33 billion Ukraine aid package to nearly $40 billion, and a House vote is possible as soon as Tuesday, two people familiar with lawmakers' thinking said.

In what would be a setback for Biden's push for more COVID-19 spending, the measure would not include any of the additional billions in pandemic spending that the president has wanted included in the plan.

The measure was described Monday by people who could speak only on condition of anonymity because they were not authorized to discuss it publicly.

Democrats' movement on the proposal comes with Russia's invasion of Ukraine in its 11th week and showing signs of becoming a grinding, long-term war. Heavy fighting in Ukraine's eastern and southern areas is causing widespread damage and significant losses on both sides, but the Russian offensive is showing few signs of progress.

Still, U.S. officials in and out of Congress have stressed that it will be critical to continue speeding assistance to Ukraine, whose forces are outnumbered.

While Democrats say more spending to combat COVID-19 is also crucial, their plan to seek votes on a package omitting those funds underscores their thinking that rushing assistance to Ukraine is their top priority. A push for a separate pandemic measure would come later, Democrats say.

The officials said Democrats' Ukraine measure would include $3.4 billion more than Biden had requested for defense spending and another $3.4 billion over what the president sought for humanitarian aid.

Biden's request, which he sent Congress on April 28, asked for $20 billion for defense spending for Ukraine, the U.S. and their allies. It also requested $3 billion for humanitarian assistance, including to help feed people around the world who rely on grains and other food from war-racked Ukraine.