Poland's Donald Tusk was due to hold talks with Estonia's Kaja Kallas, Latvia's Evika Silina and Lithuania's Ingrida Šimonytė on Sunday evening, according to officials.
The Polish and Baltic counterparts were expected to discuss a range of issues, including "the situation on the eastern border," regional cooperation and the outcome of this week's European Council summit, reporters were told.
Estonia's head of government on Sunday morning announced the meeting would not take place as she had tested positive for COVID-19.
Kallas added on the X social media platform: "Unfortunate news as I was looking forward to hosting in Tallinn Donald Tusk for his first foreign visit as well as Evika Silina and Ingrida Šimonytė, and speaking at the Grand Continent Summit on Wednesday."
"Take care and stay healthy, everyone," she added.
The Polish prime minister's Office confirmed the cancellation of the meeting.
Tusk wrote on the X platform: "Get well soon, dear Kaja Kallas. Hoping to see you and our friends from Vilnius and Riga in the nearest future. So much to talk about: borders, Ukraine, our common security. Merry Christmas to all."
(pm)
Source: PAP, Government of Estonia