HELSINKI (AP) -- Latvia's top diplomat said on Thursday he will step down in the wake of a criminal probe over the use of expensive private flights by his office when he acted as the Baltic country's prime minister between 2019-2023.

Following a meeting with Prime Minister Evika Silina, Foreign Minister Krisjanis Karins told reporters that he will leave his post on April 10, enabling lawmakers at the Saeima, or parliament, to vote on his successor the next day.

Karins, who had previously announced his interest in becoming the next secretary-general of the NATO alliance, offered no explanation or additional comments to the media.

Last week, the prosecutor general's office announced it was launching criminal proceedings over the alleged waste of public money through the use of private aviation services by Karins and accompanying delegations during his time as a prime minister.

Public criticism in the case has centered on whether all flights, including chartered private jets, used by Karins and his staff were necessary to fulfill official duties, and whether the use of charter flights - often substantially more expensive than scheduled flights - was justified in certain cases.

There are no indications that Karins himself faces charges as part of the probe into the scandal that erupted already last year and has caused public outrage in Latvia, a European Union and NATO member state with a population of 1.9 million that borders Russia.

In her comments, Silina praised Karins' decision to resign despite not being personally accused of any wrongdoing at this stage. saying he acted like "a decent Western politician."

"I believe that Krisjanis Karins has worked in good faith as foreign minister and has represented Latvia's interests very well both in the EU and NATO," said Silina, as quoted by Latvian news agency LETA.

According to Silina, who took up Latvia's top job only in September when Karins became foreign minister, she hasn't yet decided on a candidate to be the next top diplomat.