NATO jets have intercepted a group of Russian fighter planes flying over the neutral Baltic sea.

The German jets were scrambled from Estonia on Tuesday following the discovery of seven Russian jets. NATO says the interception was the biggest seen in recent years.

The discovery comes after a Russian spy plane allegedly violated Estonian airspace last week. NATO says the plane entered airspace illegally before being seen off by NATO jets. Russia has denied the claims.

Latvia's Defense Ministry has reported a rise in the number of Russian jets and warships observed near Baltic territory this year.

"All these processes cause concern. I have a question, why is such a demonstration of force needed? There must be some political reason behind it. There should not be fear of a direct threat, as we have to see the full picture about how the escalation will turn out. However, we know that any escalation can lead to unpredictable moves," Raimonds Graube, the head of Latvia's Armed Forces said last month, cited by the LETA news agency.

Russian Foreign Minister Sergei Lavrov blasted NATO's thoughtless and limitless expansion.

"Instead of making OSCE a normal organization, which would become a real security organization, ensuring security for everyone, our western colleagues took the course of thoughtless, limitless NATO expansion, telling us directly, that legal security guarantees can only be given to those who join the North Atlantic Alliance," Lavrov said in an interview with the Life News TV channel and the Izvestia newspaper, cited by Voice of Russia.

(Edited by Rayyan Sabet-Parry)