Skoda, a Czech car manufacturer and major sponsor of hockey's World Championship, says it won't be involved if Belarus co-hosts the tournament with Latvia as planned.
Protests against Belarus' government and its authoritarian president, Alexander Lukashenko, have been raging in the country since last year's election.
In addition, the IIHF is investigating Belarusian Ice Hockey Association president Dmitry Baskov, who's alleged to have been involved in the death of a political opponent.
IIHF president Rene Fasel said Wednesday that the governing body isn't considering any fallback options should it decide not to go ahead with the current plan. He added that the notion of moving the tourney exclusively to Riga - the other host city - isn't on the table.
However, Fasel said the IIHF needs to be certain it can safely hold the tournament in Belarus before formally approving it as a host considering the aforementioned factors and the COVID-19 pandemic.
"If we move forward with Minsk as a tournament host, we also must establish a system where we can be assured that the Belarus government is taking concrete actions towards fulfilling the pledges made to the IIHF, otherwise it will not be possible to hold a World Championship in Minsk due to the elevated safety issues," he said.
Fasel raised eyebrows when he met with Lukashenko this week, later admitting it went "a bit wrong" and implying he didn't want it to appear as though he was showing support for the leader, who has cracked down on the protests.
The longtime hockey executive was also seen with Baskov at a recent KHL game.
The IIHF awarded the 2021 worlds to Minsk and Riga in 2017.