Ambassador Victor Tatarintsev made the comments in an interview with Swedish public broadcaster SVT on Wednesday evening.
Relations between the two countries have been frosty for some time, with Sweden accusing Russia of showing aggressive tendencies and Russia dismissing the concerns as James Bond theories.
Speaking in Swedish, Tatarintsev said, listing a series of strategic locations in Sweden: "It is ludicrous to have any doubts that Russia has special military plans to attack Sweden, Gotland, Karlshamn, Slite… ludicrous. [sic]"
We think there was perhaps a language barrier here, and that he in fact meant to say the opposite, because he went on to clarify that Russia was not a "threat" to Sweden.
"We respect the integrity of Sweden and we have no plans whatsover to invade Sweden, so the Swedish population can sleep easy," said Tatarintsev.
It is unclear to what extent the Swedes will take the Russian ambassador's comments to heart. Earlier this year Sweden for the first time in a decade stationed a permanent military force on Gotland, considered a key strategic location in the Baltics and seen by some as a potential target for an aggressive Russia.
The interview comes amid increased top-level concern in Sweden about regional plans to rent out Slite port on the Baltic Sea island of Gotland and Karlshamn harbour in the south to Russian-owned gas pipeline project Nord Stream 2, which would run from Russia to Germany.
The Supreme Commander of Sweden's Armed Forces, Micael Bydén, has expressed concern over giving a foreign power access to Swedish infrastructure, and the foreign ministry has called representatives from Gotland and Karlshamn to a special meeting on December 13th to discuss security-related issues.
Prime Minister Stefan Löfven has been reluctant to comment on specifics, but told Swedish media at a press conference on Wednesday that he had "doubts" about the Nord Stream 2 project in general.
On a visit to Stockholm earlier this year, US Vice President Joe Biden also declared Nord Stream 2 to be undesirable, calling it a “bad deal” for Europe.