WASHINGTON (Reuters) -The U.S. will not complete scheduled deliveries of crude oil into the Strategic Petroleum Reserve until the end of the year due to maintenance, as much as seven months behind schedule, the Department of Energy said on Thursday.

Former President Joe Biden's administration scheduled 15.8 million barrels of deliveries to the SPR from January through May. So far this year only 8.8 million of that has been delivered to the reserve.

"Due to site maintenance, the SPR rescheduled crude oil secured from previous solicitations, as well as exchanges, through December 2025," an Energy Department spokesperson told Reuters.

Biden carried out several sales from the Strategic Petroleum Reserve including 180 million barrels in 2022, the largest ever, in an attempt to control spiking gasoline prices after Russia invaded Ukraine.

President Donald Trump vowed on his first day in office in January to fill the SPR "right to the top", in an effort to support the domestic oil industry, but it is taking time.

Energy Secretary Chris Wright has estimated it would take $20 billion and years to refill the reserve to the level it was before the sales. Trump's tax-and-spending bill allocates about $1.5 billion for purchases and SPR maintenance.

Wright has also blasted Biden's large sale from the reserve, saying it caused hundreds of millions of dollars in damages.

When asked for a breakdown of those damages, his department said the 180 million barrel sale resulted in $2 million in emergency repairs, $35 million in costs to move the oil and $243 million in costs from delays to congressionally-directed maintenance.

The Biden administration said in November it had bought back 59 million barrels for the SPR after the 2022 sale at an average price of less than $76 a barrel, far lower than the $95 a barrel at which it sold oil in 2022. That resulted in a profit of about $3.5 billion, Biden's DOE said at the time.