Povilas Poderskis, the city's municipal administration director, says the aim is to prepare for a scenario where the area of radioactive contamination covers a 30-kilometer radius from the nuclear facility, including Vilnius.
"The scenario will include an evacuation of a certain part of Vilnius; people will be directed to the so-called decontamination stations," Poderskis said.
"A station will be set up outside the Siemens Arena where we'll have people change their clothes, put them on buses and escort them along Ukmerge Street in the direction of Ukmerge", he added.
The exercise will assess the readiness of municipal companies and services to respond to threats and will also include a simulation of cyber-attacks.
"We'll disrupt the work of public institutions and we'll see how all of us are prepared," Poderskis said.
The municipal official criticized national authorities for their sluggishness in preparing for the launch of the Astravyets plant and potential incidents.
According to Poderskis, the city's administration already sees "huge holes" in funding, equipment, and interaction with other authorities.
For example, under the drill scenario, "civil defense personnel receive information on radiation contamination," the director said.
"The government doesn't finance such on-duty staff; so we simulate that there is such staff while in fact there aren't," he said.
Lithuanian authorities say the Astravyets plant under construction around 50 kilometers from Vilnius and less than 30 kilometers from the Lithuanian border fails to meet international safety and environmental standards, an allegation that Minsk denies.
Belarus plans to launch the first reactor at Astravyets this fall.