The Swedish security police Sapo said on Wednesday they have arrested a person on suspicion of spying for Russia.

"The person is suspected of having been recruited as an agent by a Russian intelligence officer who works under diplomatic cover in Sweden," Daniel Stenling, head of Sapo's counter-espionage unit, said in a statement.

The arrest took place in central Stockholm on Tuesday evening, Sapo spokesman Gabriel Wernstedt told dpa, but he declined to offer details on the suspect or his or her nationality.

The Sapo statement said the suspect worked in an undisclosed high-technology industry with information known to be of interest to foreign intelligence services.

The case has been running since 2017. There were at present no further links to other cases, Wernstedt said.

Sapo's brief includes protecting national security and Sweden's democratic system of government, averting espionage attempts as well as terrorism attacks.

A decision to place the suspect in pre-trial detention was due at the latest by midday Friday.