"A powerful explosion in front of the Swedish consulate caused serious damage to it and neighbouring buildings but no casualties," Colonel Abdullah Zaidi said.
The Swedish mission is one of the few remaining diplomatic offices remaining in Benghazi, the cradle of the 2011 uprising that ousted dictator Muammar Gaddafi and now a hotbed of lawlessness.
It is located in the Al-Fouihet district of the city, not far from the Egyptian consulate, which was bombed in August.
These attacks are routinely blamed on Islamists, but have never been claimed.