SEATTLE — Ahead of Seattle’s COVID-19 vaccination deadline for city workers, Interim Police Chief Adrian Diaz is urging department employees to get vaccinated, warning of a possible staffing challenge if they fail to do so.

In a letter sent to staff Friday, Diaz said the agency appears to still have hundreds of unvaccinated employees, based on the latest vaccination information submitted to the department, the Seattle Times reported.

The department has struggled with staffing shortages and has lost at least 250 officers in the past two years.

In his letter, Diaz said the Police Department has constructed staffing plans to ensure the continuity of services, but needs to know how many individuals are cleared under the city’s requirement, to minimize personnel disruptions.

Under a directive issued by Seattle Mayor Jenny Durkan, city employees are required to be fully vaccinated by Oct. 18 and have until Oct. 4 to either receive their second vaccine dose or a single dose of the Johnson & Johnson vaccine to be in compliance with the deadline.

Of the city’s 12,000 employees, more than 9,000 have submitted vaccination confirmations so far, a spokesperson for the mayor’s office told The Seattle Times. In addition, there have been 600 religious exemption requests and 98 medical exemption requests.

The deadline for Seattle Police Department employees to submit proof of vaccination is Oct. 5.