Roughly 23,000 people will have to wait a week for their first dose.

As the country continues to face supply issues for the coronavirus vaccine, New York City officials announced Wednesday that it had to postpone the first dose appointments for the next three days for 23,000 people.

Mayor Bill de Blasio and the New York City Health Department said they were informed by the distributor of the Moderna vaccine that a shipment of 103,400 doses that was supposed to be delivered Tuesday was delayed. As a result, first dose appointments at 15 city vaccination sites from Jan. 21 to Jan. 24 had to be postponed, according to city health officials.

“We already were feeling the stress of a shortage of vaccine. Now the situation has been made even worse,” the mayor said during his daily news conference.

Appointments at the 15 sites between Jan. 21 and Jan. 24 for New Yorkers who are scheduled for their second dose will remain as planned, Dr. Dave A. Chokshi, the city’s Health Commissioner, said during the news conference.

Patients who had their appointment canceled will be notified through an email and call from the affected vaccination site, according to the Health Department. The new appointments for those first dose shots would take place at the same time next week, the health department said.

During a separate news conference later in the day, Melissa DeRosa, the secretary to Gov. Andrew Cuomo, said there were no postponements for appointments at state-run vaccination sites, which include two in New York City.

“We were incredibly conservative with the number of appointments that we set up there,” she said.

Last week, New York state expanded its vaccine eligibility list to include seniors above 65 years old, teachers and other high-priority employees.

As of Jan. 20, New York City has received 940,825 coronavirus vaccines, 688,075 first doses and 252,750 second doses, Health Department data showed. It has administered 494,596 total doses, 434,138 first doses and 60,458 second doses, the data showed.

De Blasio said he hopes to see an improved vaccine delivery and implementation under the Biden administration, which has proposed several options to increase vaccine supply, including the use of the Defense Production Act.

“The Defense Production Act is going to be absolutely critical because these two companies that are authorized right now are both U.S. based companies. And so therefore in theory you should be able, to ramp up production specifically for the U.S. population,” Dr. Jay Varma, the mayor’s senior advisor for public health, said during the news conference.