Abbott Laboratories and the U.S. Food and Drug Administration are on track to reopen the company's Sturgis, Michigan, baby formula manufacturing plant within one or two weeks, FDA Commissioner Robert Califf said on Thursday.

Abbott, the biggest U.S. supplier of powder infant formula including Similac, on Monday agreed with the FDA on steps needed to resume production at the manufacturing plant.

"I'm pleased to say today we've already made significant progress and I think we are on track to get it open within the next week to two weeks, most likely at the outer bound two weeks," Califf told a U.S. House of Representatives panel.

The company recalled infant formula products and closed the plant in February after reports of serious bacterial infections in four infants, worsening a shortage among multiple manufacturers that began with pandemic supply chain issues.

The FDA was investigating Abbott after reports that four babies who had been fed formula made there became ill from Cronobacter sakazakii infections.

The agency cannot conclude whether cases of ill babies are directly related to the Abbott plant until its investigation is concluded, Califf said.

The FDA is working closely with Abbott and that he personally receives two daily reports on the efforts to restore the plant, he told lawmakers.

"It looks like it is going well, that Abbott has remedied a number of the issues, and we're going to make sure it gets done as quickly as possible."

The FDA is confident more product "can quickly hit U.S. stores," he said, but it will still be weeks until formula supplies are back to normal. People are buying more formula now than before the recall, making distribution harder, he added.

The nationwide shortage has left parents scrambling to feed their babies and the U.S. government searching for short-term fixes while grappling with longer-term solutions.

President Joe Biden invoked the Defense Production Act on Wednesday to help manufacturers obtain ingredients to ramp up supply.

The House on Wednesday passed two bills, including one providing $28 million in emergency FDA funds supported by 219 Democrats and 12 Republicans. It was opposed by 192 Republicans.

A second measure, passed 414-9, would guarantee low-income families can continue using their benefits to buy formula under a federal program for women, infants, and children known as WIC.

Both bills must also pass in the closely divided Senate.

'DERELICTION OF DUTY'

House Appropriations Committee Chairwoman Rosa DeLauro grilled Califf, who appeared before an Appropriations subcommittee to discuss the FDA's budget request for the 2023 fiscal year, over its response to the shortage.

The FDA said on Monday it would allow baby formula imports from foreign makers that do not usually sell their products in the United States to help ease the shortage.

"I remain concerned about the safety of the formulas that end up on our shelves," said DeLauro, adding she was worried "the FDA's recently released guidance does not go far enough to ensure formula is safe."

She also criticized the FDA for acting too slowly, having received a whistleblower report in October. DeLauro cited the report last month when she sought a government probe.

"Whomever looked at that report felt that there was no need to respond at all from October to February until there was a recall. That is a dereliction of duty, in my view," she said, referring to then-acting Commissioner Janet Woodcock.

Califf has tasked Woodcock with a bigger leadership role on food issues as part of his response.

"Now it would appear that person is going to oversee this effort. That is the fox in the henhouse," said DeLauro.