Lithuania's Health Ministry reported 999 new confirmed coronavirus cases on Thursday and another four deaths from Covid-19.
A third of the new cases, 299, were reported in Vilnius County, 180 came from Klaipėda County and 138 from Kaunas County.
Infections continue to spread in healthcare institutions and schools, according to the National Public Health Centre (NVSC).
Clusters in Vilnius have been linked to the National Library, the Central State Archive, and the night club Materialistė.
In Klaipėda, one outbreak is linked to the Lithuanian navy.
Night clubs Amnesia, Taboo and the restaurant Legenda in Kaunas have also been sites of coronavirus infections.
Three of the four coronavirus casualties were in their 70s and had prior health conditions, according to the NVSC. The fourth deceased person was in their 90s.
The country's total count now stands at 19,910 infections, while the death toll is 186. Another 63 coronavirus-infected patients have died of other causes.
The country currently has 13,557 active coronavirus cases and 5,285 recoveries.
Over 36,000 people are currently in isolation.
Lithuania performed 14,594 coronavirus tests over the past 24 hours, according to the Health Ministry.
The country is going into a nationwide three-week quarantine on Saturday, which will include restrictions on socialisation and some businesses.