Bildt said on Twitter the government of President Alexander Lukashenko described the ambassador, Stefan Eriksson, as being "too supportive of human rights," the EUobserver reported.
"Outrageous. Shows nature of regime," Bildt said.
A Swedish public relations firm dropped teddy bears on Belarus in July. The bears, dropped with parachutes, had signs calling for human rights and free speech.
Bildt said the Belarus ambassador to Stockholm will be asked to leave.
Catherine Ashton, the European Union's foreign policy chief, said the Policy and Security Committee will discuss Belarus next week.
Andrei Savinykh, a spokesman for the Belarus foreign ministry, described Eriksson as "destroying" relations between the two countries.
"If the Swedish side is eager to aggravate the situation, we will be forced to respond adequately," he told the Belta news agency.
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