He argues that it is unacceptable to blame an entire group for one person's actions.
“We who believe in the Swedish values of openness and tolerance have a responsibility to fight the Islamophobia and prejudice which can follow in the wake of terror,” writes Ullenhag.
“We should never allow one individual's act to result in an entire religion being seen as suspect or having a group saddled with collective guilt.”
He points out that "more than 99.9 percent" of Sweden's estimated 400,000 Muslims are not among the list of roughly 200 violent Islamic extremists in the country identified by Swedish security service Säpo.
Ullenhag said he shared concerns expressed to him by Muslim students in the days following the December 11th suicide bombing in Stockholm that the blasts would affect perceptions of them and their families.
He also cites a recent study from Sweden's Forum for Living History (Forum för levande historia) which found that tolerance among Swedish youth for Muslim, Jews, and Roma had decreased in recent years.
In an effort to counteract potential discrimination against Swedish Muslims that could result from the suicide bombing, Ullenhag is meeting on Thursday with a number of prominent leaders from Sweden's Muslim community.
“The purpose of the meeting is to discuss how the government can deepen its work to combat discrimination and an increasing Islamophobia,” writes Ullenhag.
“I want to listen to the experiences of Swedish Muslims and talk about what we can do to reduce polarisation and stop barriers between groups and people from taking root.”
Ullenhag further emphasised that Sweden should never abandon its ideals of openness and tolerance in the fight against terrorism.
“If a suicide bomber succeeds in creating large divisions and increased intolerance – then terror has won,” he writes.