WASHINGTON (Reuters) - The Trump administration has decided it cannot authorize new flood insurance policies, citing the partial shutdown of the federal government due to a budget impasse in Congress and potentially putting thousands of home sales in limbo.

The Federal Emergency Management Agency (FEMA), which oversees a federal program that insures about 5 million homes and businesses, on Wednesday posted a notice on its website that the program will not be able to “issue new contracts for flood insurance during a lapse in authority unless Congress passes legislation.”

The National Association of Realtors estimated the decision could disrupt up to 40,000 home sales each month.

FEMA said that during the shutdown, the government-backed National Flood Insurance Program will continue to pay all claims on policies taken out before midnight on Dec. 21.

The federal government has been partially shut down since Saturday because of an impasse over President Donald Trump’s demand for $5 billion in taxpayer funding for a proposed Mexican border wall. Last week Trump said his administration was prepared for a lengthy shutdown.