"Once again we see that journalists have become targets in war and conflicts," says Margot Wallström to Swedish Radio News.
Radio correspondent Maria Persson Löfgren suffered injuries, including severe bruising and a cut which needed hospital attention.
The attack was condemned as "hooliganism" by a spokesman for the Russian president, reports news serviceMeduza. Spokesman Dmitry Peskov is hopeful that police will find the attackers.
Sweden's international prosecutor is working to see whether a case can be brought in Swedish courts against any suspect.
Opposition politician Birgitta Ohlsson says she has little faith that the Russian authorities will bring anyone to justice, in what she calls "an increasingly authoritarian Russia under Putin's leadership."