Stockholm:
Sweden on Friday said it has lodged a protest with Russia after the incursion of two Russian fighter planes into Swedish airspace.
"The foreign ministry Friday summoned Russia's ambassador in Stockholm to tell him of its protests with regard to this incident," the ministry said in a statement.
The two Russian fighter planes violated Swedish airspace on Wednesday for about 30 seconds, near the eastern island of Oland, military officials said.
In his blog, Swedish Foreign Minister Carl Bildt denounced the incident as "a major violation" and the worst he has seen since becoming Sweden's top diplomat in 2006.
The head of the Liberal party Jan Bjorklund was quoted in the Expressen newspaper as saying the incursion was "more serious than previous violations".
"We have been seeing for some time military activity increasing in the region of the Baltic Sea," he told the paper.
The countries in the Baltic region have become more concerned about security and Russian aggression after Moscow's annexation of Crimea in March and its alleged military support for pro-Russian separatists battling Kiev government forces in eastern Ukraine - a claim the Kremlin denies.