Ukraine on Tuesday reported the highest number of COVID-related deaths since the start of the pandemic, with 538 people dying from the virus within the past 24 hours, the country’s Ministry of Health reported.

The country has also been reporting the lowest rate of COVID-19 vaccination in all of Europe, with only 15% of its population fully vaccinated, according to the Our World in Data. Ukraine has a population of about 41 million.

President Volodymyr Zelensky has implemented a new vaccine mandate set to take effect on Thursday that will require people to provide either a vaccination certificate or a negative test to board a train.

However, vaccine hesitancy has not been Zelensky’s only worry during the pandemic. There has also been a growing number of illegal schemes selling fake COVID credentials, such as negative PCR tests and vaccine certificates, so people can get around restrictions implemented during the pandemic.

Some of these forgeries have been done by doctors, laboratory representatives and intermediaries. Zelensky noted that these violators are already being prosecuted but it is unclear how many fraudulent COVID credentials have been administered.

In a Tuesday meeting, Zelensky and other Ukrainian officials met to discuss how to handle the growing fraud. They also discussed strategies on how to ramp up vaccination.

"It is clear that it is more convenient for people to get vaccinated on Saturday and Sunday. The task of the Ministry of Health and local authorities is to provide such an opportunity," Zelensky said.

Minister of Health Viktor Lyashko noted in the meeting that 95% of those hospitalized with COVID-19 are unvaccinated, reinforcing the need to accelerate the country's pace of vaccination.

Ukraine has reported an average of 14,348 cases a day over the past week. The New York Times noted that the country’s low testing rate means the actual number of new infections may be far higher.