Estonia urged the head of NATO on Wednesday to investigate the accidental launching of an air-to-air missile in its airspace on Tuesday by a NATO Air Policing mission plane.
The Estonian government said in a statement Prime Minister Juri Ratas had discussed the incident with NATO Secretary General Jens Stoltenberg over the phone.
"I told the secretary general of NATO that it is a serious incident and we are understandably concerned about this in Estonia. Thank God that, as far as we know, no one was hurt as a result of the incident," Ratas said in the statement.
Estonia, a Baltic state bordering Russia and Latvia, is a member of the North Atlantic Treaty Organization (NATO).
"I asked Jens Stoltenberg to take yesterday's incident very seriously and promptly identify the circumstances," Ratas said.
Within NATO's air policing peacetime mission, member states assist allies that lack the means to police the skies over their own territories, the military alliance says on its website.