Illinois officials said Saturday they are expecting 60,000 doses of Pfizer’s COVID-19 vaccine this week from the federal government, a number that had been in question for days, causing angst among the state’s public health officials responsible for planning vaccine schedules.

Governor JB Pritzker first sounded the alarm Wednesday, saying the federal government was planning to ship only about half the number of doses it had originally promised, a claim echoed by other states but denied all week by the Trump administration.

Saturday, Gen. Gustave F. Perna, who heads up Operation Warp Speed and is responsible for logistics of vaccine distribution to the states, said a “planning error” caused the federal government to overpromise how many doses would be arriving in some states. “It was my fault,” the general said.

Perna said the miscalculation forced him to lower vaccine allocations to states. “So to the governors,” he said, “please accept my personal apology if this was disruptive in your decision-making.”

Illinois is among more than a dozen states getting less vaccine this week than they had anticipated. The state received 109,000 doses last week, with the first Illinoisans rolling up their sleeves for the vaccine on Tuesday.

Pritzker has said the federal government has assured him that Illinois will receive the second doses of the vaccine that are needed to fully vaccinate those health care workers who received the first dose last week. The Pfizer COVID-19 vaccine requires two doses, spread over a three-week period of time.

Knowing the timing and precise number of vaccines arriving in the state is critical in part due to handling requirements. The Pfizer vaccine must be kept at ultra cold temperatures and used within five days after being removed from its unique cold-storage container.

Illinois has 655,000 health care workers who are first in line to get the vaccine.

State officials said the first shipments of the Moderna vaccine, authorized by the Food and Drug Administration late Friday, are also expected this week.

Linda Lutton is a reporter for WBEZ. Follow her @lindalutton.