Reinfeldt was talking to reporters on Sunday afternoon after an event at the Royal Palace. When asked about the conflict in Ukraine, where Russian soldiers have moved in to Crimea and Ukrainian forces are mobilizing, he said Russia's actions were "understandable".
"It's somewhat understandable that Russia is acting on concerns about the Russian minority of Crimea and eastern Ukraine, but not in the way they're doing it. There are of course methods for talking to the Ukrainian government and calm down the situation in that way," he told reporters.
His remarks caught the attention of Foreign Minister Carl Bildt, among others.
"I don't think there has been that much concern among the Russian minority if I'm being honest," he told SVT's Agenda programme on Sunday night.
Bildt has previously said that events in Ukraine were a "violation of international law".
Others also reacted to the prime minister's choice of words.
"This is one of the strangest and most disturbing statements from a Swedish prime minister that I can remember," Wilhelm Agrell, a professor of intelligence analysis at Lund University, told the Svenska Dagbladet newspaper.
While Reinfeldt's press spokesman took to Twitter to explain that the original comments were taken out of context, the prime minister himself made an appearance on Godmorron Sverige in an attempt to clear the air.
"The starting point to understanding this is that there is a Russian-speaking part of Ukraine where people ethnically consider themselves to be Russian. But that doesn't change the fact that Russia's behaviour is reprehensible," he said.