Estonian Prime Minister Kaja Kallas has, as expected, submitted her resignation in order to serve as the European Union's top diplomat.
Kallas informed the parliament in Tallinn of her decision on Monday and submitted her letter of resignation to President Alar Karis.
Under to the Estonian constitution, Kallas' move automatically leads to the resignation of the entire government of the Baltic EU and NATO member state.
Until a new Cabinet of ministers is confirmed, however, it will remain in office on a caretaker basis.
Kallas, 47, was nominated by EU leaders in June to become the bloc's foreign policy chief, replacing Josep Borrell of Spain.
The Kallas government has been a staunch supporter of Ukraine in fighting off the Russian invasion and backs a firm policy towards Moscow. Earlier this year, her name was added to the Russian Interior Ministry's list of those wanted on unspecified criminal charges.
She became Estonia's first female prime minister in 2021.
Kallas' centre-right Reform Party has chosen Climate Minister Kristen Michal as a possible new prime minister, but is currently holding talks with its two coalition partners. Negotiations have been ongoing for just over a week.
A three-party alliance consisting of the Reform Party, the Social Democrats and the liberal Estonia 200 party has been in power in Estonia since spring 2023.
President Karis, who must give the official order to form a government and appoint the new Cabinet, announced that he wanted to meet with all parties represented in parliament.
"Estonia needs a government that governs and makes decisions that help boost the economy and ensure our security," he said.
Estonia, with its 1.3 million people, borders Russia. The war in Ukraine is seen as a direct threat to national security.
Estonian media estimated that, if all goes to plan, the new government could take up its work at the beginning of August.
