The man was arrested on Friday and was found to be in possession of two tonnes of explosives, Aftonbladet reports.
Sweden’s foreign ministry has confirmed that the man was apprehended in connection with plans to bomb a number of western embassies, including Sweden’s.
Authorities in Pakistan have not revealed any further details about the suspect.
Sweden’s military presence in Afghanistan is believed to have provided the motive for the planned attack.
There are currently 70,000 foreign troops serving in Afghanistan. Of these 50,000 are part of the NATO-led ISAF – International Security Assistance Force – and are operating in the country on a UN mandate.
In addition there are 20,000 troops participating in the US-led OEF – Operation Enduring Freedom.
The almost 400 Swedish troops in Afghanistan are part of the ISAF force. Sweden recently announced an increase in its commitment to 500 soldiers.
In November 2005 two Swedes were killed in the vicinity of Mazar-i-Sharif and there have been a number of incidents involving Swedish troops that have come under fire.