The U.S. Energy Department said May 13 it will buy up to 1 million barrels of sweet crude for the government's emergency petroleum reserve as part an effort to help producers struggling as the coronavirus strangles oil demand.

The move came after the department canceled an initial plan to buy up to 30 million barrels for the Strategic Petroleum Reserve, or SPR, after Congress failed to fund it as some lawmakers complained it would help oil companies during the coronavirus pandemic.

U.S. President Donald Trump had ordered Energy Secretary Dan Brouillette in March to fill the SPR to the top, and the department tried to find funding to purchase a total of 77 million barrels, which would have brought the reserve to its capacity of about 714 million barrels.

The purchase of up to 1 million barrels "will serve as a test of the current conditions of physical crude oil available to the SPR as opposed to the financial market trading WTI Nymex futures contracts," the department said in a release. The department will purchase the oil from small to midsize domestic producers, it said.

The Energy Department did not immediately respond to a question about whether there would be further purchases if the test yielded favorable results.

After it canceled the 30 million barrel purchase, the Energy Department devised a plan for companies to rent space to store some oil in the SPR. In late April, the Energy Department said nine companies including Chevron Corp. and Exxon Mobil Corp. had agreed to rent space to store 23 million barrels of crude.

About 4.8 million barrels of oil have been delivered so far to the SPR in late April and in May under the leasing program, the Energy Department website showed.