Top infant formula makers, including Reckitt Benckiser, Nestle and Danone SA, are also ramping up supplies to the country.
Here is a timeline of how the crisis unfolded and measures being taken to resolve it:
Abbott recalls dozens of types of powdered baby formulas, including Similac, Alimentum and EleCare, made at its Sturgis, Michigan plant after four consumers complained about bacterial infections in infants who had consumed those products; Recalled products had an expiry date of April 1, 2022 or later.
China's custom officials warn consumers against buying and consuming certain of Abbott's infant and baby products.
Abbott expands recall to include some Similac PM 60/40 products based on a fifth complaint of a bacterial infection.
House Appropriations Committee Chairwoman Rosa DeLauro asks for an investigation https://delauro.house.gov/media-center/press-releases/chair-delauro-requests-investigation-fda-handling-abbott-powdered-infant into the FDA's handling of the Abbott recall.
The Salmonella Newport illness, which was previously included in the investigation of complaints and illnesses, has been removed, the FDA says. The regulator has determined that there is not enough information to definitively link the illness to powdered infant formula.
FDA probe of Abbott's Michigan facility finds a harmful bacteria called Cronobacter sakazakii on the surface of some areas near infant formula production and reveals Abbott did not have a control system covering all stages of processing to prevent microbe contamination.
Abbott cuts full-year sales growth forecast, citing the voluntary recall of the infant formula products but keeps profit estimate. Abbott calls the recall a "short-term hindrance".
House Appropriations Committee Chair Rosa DeLauro in a testimony submits a report acquired from a whistleblower, who had worked at the Abbott facility and had filed a complaint with the FDA in September 2021.
Abbott says it will release limited quantities of nutrition products that were put on hold after February recall.
Major U.S. retailers including Target Corp, CVS Health Corp, Walgreens Boots Alliance and Kroger Co place purchase limits on infant formula products.
Abbott says it has been prioritizing production of formula at other plants and ships formula from its Ireland facility.
U.S. lawmakers plan to hold a hearing on May 25, the House Energy and Commerce Committee says, calling the shortage "increasingly alarming".
Abbott says it could restart production at its Michigan facility within two weeks following approval from the FDA, but add that it would take six to eight weeks for the product to hit the shelves after the resumption.
President Joe Biden meets with executives from baby formula manufacturers and retailers including Target, Walmart and Nestle's Gerber to address the shortage.
U.S. House Appropriations Committee says FDA Commissioner Robert Califf is set to testify the agency's response to the shortage before the panel on May 19.
The U.S. House Oversight Committee plans to investigate the shortage, saying it has sent letters seeking information to the four largest manufacturers of baby formula - Abbott Nutrition, Mead Johnson Nutrition, Nestle USA and Perrigo.
U.S. Centers for Disease Control and Prevention (CDC) closes its investigation on Abbott, while Abbott said it has air shipped millions of cans of baby formula powder into the United States from its facility in Ireland.
Store-brand baby formula maker Perrigo Co says shortages and heightened demand may last for the rest of the year.
The FDA says the United States will allow imports of infant formula from foreign makers that do not usually sell their products in the country.
Abbott reaches agreement with the FDA on the steps needed to resume production at its Michigan plant.
U.S. House Democrats unveil a bill to provide $28 million in emergency funds to the FDA to help it respond to the shortage and bolster supervision of the industry.
Nestle SA told Reuters it was flying supplies to the country from the Netherlands and Switzerland. Reckitt Benckiser, the second largest U.S. milk formula supplier, is boosting baby formula production by about 30%.
U.S. President Biden invokes the Defense Production Act to help manufacturers obtain the ingredients needed to ramp up supply.
Several Canadian retailers have imposed purchase limits on baby formula products, says Retail Council of Canada spokesperson, adding the country has not been as hard hit by the shortage.
Abbott and the FDA are on track to reopen the company's Michigan plant within one or two weeks, FDA Commissioner Robert Califf says.
French baby formula maker Danone SA has ramped up shipments of infant formula from Europe to the United States, according to U.S. customs data and shipping consultancy Ocean Audit.
(Reporting by Deborah Sophia and Leroy Leo in Bengaluru; Editing by Anil D'Silva and Sriraj Kalluvila)