HELSINKI — The decision by Turkish authorities to declare 10 foreign ambassadors — including seven from Europe — as persona non grata is a "tough reaction" and "regrettable," the Finnish Prime Minister said on Sunday.

The 10 ambassadors called for the release of businessman and philanthropist Osman Kavala — jailed in 2017 despite having not having been convicted of a crime — in a joint statement last week.

Turkish President Recep Tayyip Erdogan said that the statement was an “impudence” and ordered the ambassadors to be declared undesirable.

“I gave the instruction to our foreign minister and said ‘You will immediately handle the persona non grata declaration of these 10 ambassadors,’” Erdogan told supporters during a rally in Eskisehir.

“They will recognize, understand and know Turkey. The day they don’t know or understand Turkey, they will leave.”

The diplomats, including the ambassadors of France, Germany, Netherlands, Canada, Denmark, Sweden, Finland, Norway, New Zealand, and the US, were summoned to the foreign ministry on Tuesday.

Finnish Prime Minister Sanna Marin told public broadcaster YLE on Sunday that "this is a tough reaction" from Erdogan.

“This is a very regrettable situation. We’ve considered it important that the decisions of the European Court of Human Rights are respected and complied with, and therefore have called for the release of this human rights activist,” Marin said.

She also said that Helsinki was engaged in a dialogue with Turkish officials and was waiting for further information from Ankara before “drawing any conclusions”.

By Sunday afternoon, none of the four Nordic countries had received an official notification from Turkey's foreign ministry on their ambassadors being labeled with a persona non grata status.

“However, I can state that we’re in close contact with our friends and allies about the case,” Danish Foreign Minister Jeppe Kofod told broadcaster TV2 late Saturday.

A declaration of persona non grata against a diplomat usually means that an individual is banned from remaining in their host country.

Kavala, 64, was acquitted last year of charges linked to nationwide anti-government protests in 2013, but the ruling was overturned and joined to charges relating to a 2016 coup attempt.

International observers and human rights groups have repeatedly called for the release of Kavala and Kurdish politician Selahattin Demirtas, who has been jailed since 2016.

They say their imprisonment is based on political considerations. Ankara denies the claims and insists on the independence of Turkish courts.

The European Court of Human Rights called for Kavala's release in 2019, saying his incarceration acted to silence him and wasn't supported by evidence of an offence. The Council of Europe says it will start infringement proceedings again Turkey at the end of November if Kavala is not released. — Agencies