The Security Service (Säpo) has carried out several operations, including house searches and technical seizures, at various locations in Sweden.
The man who was remanded in custody by the Stockholm District Court on Monday is in his 30s and lives in western Sweden.
"My client denies the crime," the man's defense attorney, Isak Åberg, told Expressen.
A man in his 40s was arrested and detained last week on suspicion of the same crime.
They are both suspected of serious crimes for allegedly transferring advanced products to Russia in various ways. The crimes are said to have taken place in Sweden between June 10, 2025, and May 5 of this year.
It is an area we are taking seriously, and we believe Russia's continued warfare depends on access to this type of product from the West and from Sweden, says Säpo's deputy operations chief, Christoffer Wedelin.
A serious sanctions violation means someone knowingly violates international sanctions, such as trading in military equipment. The crime can result in imprisonment for up to six years.
Säpo does not rule out that more operations may take place in the future.
