WASHINGTON (Reuters) - The U.S. Federal Emergency Management Agency will run out of disaster assistance funding on Friday unless Congress approves more money, two Florida senators warned on Thursday. As Hurricane Irma barrels through the Caribbean on its way to an expected landfall on Florida on Sunday, the Senate approved a measure 80 votes to 17 to more than double funding to $15.25 billion to FEMA and local block grants to handle natural disasters. The House is expected to approve the measure later this week. It already approved $7.85 billion on Wednesday.  FEMA is stretched, and, of all things, FEMA runs out of money unless we act by tomorrow,  Democrat Senator Bill Nelson said in a speech on Thursday, following a letter he wrote with Republican Senator Marco Rubio to congressional leaders warning that more funds were needed. The bill also extends the National Flood Insurance Program through Dec. 8 that was set to expire on Sept. 30. The government-subsidized insurance program helps homeowners in flood-prone areas receive coverage. It is nearly $25 billion in debt and members of both parties want to reform it. FEMA declined on Thursday to say how much remained in its Disaster Relief Fund, which had just over $1 billion on hand as of Tuesday, less than half the $2.1 billion it had last week. The agency has received a record number of disaster assistance requests from victims of Hurricane Harvey.  We re not going to let money get in the way of saving lives,  FEMA director Brock Long told broadcaster CBS on Wednesday.  Congress knows what they need to do.  David Lapan, a spokesman for the Department of Homeland Security, which oversees FEMA, also declined to say on Thursday when the fund would be depleted, but said it would not be long without congressional action. On Thursday, U.S. President Donald Trump approved a major disaster declaration for the U.S. Virgin Islands, which makes residents eligible for FEMA and other government grants for temporary housing and home repairs, low-cost loans to cover uninsured property losses, and other programs. In response to Irma, FEMA said staff had been deployed to the U.S. Virgin Islands and Puerto Rico and more than 1,000 personnel were ready to respond in Florida, South Carolina, North Carolina and Georgia. Provisions include millions of liters of water, meals, medical equipment and generators. 