"As of 8 a.m. this morning, only eight of the 260 plus beds at our regional COVID-19 hospital were available," Remigijus Simasius said. "The situation is really serious."

Around half of the COVID-19 patients are aged under 65 years, meaning that they do not yet fall into vaccination priority groups, he noted.

Officials from Vilnius Municipally and Vilnius University Hospital Santaros Klinikos, the coordinator of the pandemic situation in the region, are discussing further steps on Monday, according to the mayor.

"Basically, we have two options: either to expand the (COVID-19) ward in Santaros, or that in the clinical hospital," he said.

The mayor said that the AstraZeneca vaccine "isn't a sell-out", because some people prefer to wait for another vaccine.

"We have around 2,000 unbooked vaccine appointments today. At the end of the day, we'll have a total of 8,000 Pfizer vaccine doses, and 3,000 unused doses of the AstraZeneca vaccine, with another 3,000 expected to arrive in a few days," he said.

Vilnius Municipality is inviting people aged 65 and over to register for a Pfizer vaccine shot from Monday to Thursday, Simasius said, adding that some 55 percent of residents in the age group had been vaccinated so far.

The capital is planning to start vaccinating people aged 55 and over on Friday, according to the mayor.