Mexican President Andres Manuel Lopez Obrador said on Friday the United States would probably send his country five million more doses of AstraZeneca’s COVID-19 vaccine, as the company admitted production in Latin American had suffered multiple setbacks.

Mexico is struggling with behind-schedule local AstraZeneca production and shortfalls in deliveries from foreign suppliers and has asked the United States to help with more vaccines.

The request is in addition to some 2.7 million AstraZeneca doses Washington sent to Mexico in March.

“It’s probable that they’ll help us with a loan, while the AstraZeneca plant in Mexico gets up and running,” Lopez Obrador said at a regular news conference.

The US State Department did not respond to a request for comment.

Under a deal reached last year, the mAbxience laboratory in Argentina manufactures the active ingredient of the vaccine and ships it for bottling to a factory in Mexico owned by a company called Liomont.

The shots are to be delivered across Latin America, excluding Brazil, which has a separate production deal.

Argentina has delivered cargos of the active ingredient to Mexico, but Liomont’s commercial production has slipped from an original target of March.

In a statement shared with Reuters on Friday, AstraZeneca said deliveries of the shots would now begin before the end of June.

AstraZeneca said it regretted the setbacks, which it attributed to limited access to critical supplies, lower-than-expected process yields from initial vaccine batches, and longer times to meet internal “site qualifications” for those batches.

“This will delay the launch of our vaccine in countries across Latin America to be supplied from this supply chain,” AstraZeneca said, without giving more details of what had caused the problems.

The Mexican government has said the Liomont factory has undergone major upgrades to produce the AstraZeneca vaccine, and that it has taken longer than expected for the factory to win regulatory approvals.