"Freedom of expression is a fundamental part of democracy.
But what is legal is not necessarily appropriate," writes the prime minister on Twitter.
“Burning books that are sacred to many is a deeply disrespectful act.
I want to express my sympathy for all Muslims who are offended by what has happened in Stockholm today," continues Kristersson.
Made demands on Sweden
The far-right provocateur Rasmus Paludan burned a copy of the Muslims' holy book, the Koran, near the Turkish embassy in Stockholm on Saturday.
The provocation has sparked anger in Turkey, which on Friday summoned Sweden's ambassador to the country.
According to sources for the Reuters news agency, Turkey issued a "strong condemnation" of Paludan's planned Koran burning and demanded that the demonstration permit be withdrawn.
Canceled visit to Turkey
Defense Minister Pål Jonson (M) has also had to cancel his visit to the Turkish Defense Minister in Turkey next week.
Several demonstrations were held in Stockholm on Saturday, both in support of and against Turkey and the country's president Recep Tayyip Erdogan.
No disturbances were reported in connection with the demonstrations, according to the police.
On Saturday evening, a small group of people also protested outside Sweden's consulate general in Istanbul, Turkey.
Some of them chose to set fire to a Swedish flag.