A Stockholm court on Monday convicted a man of inciting ethnic hatred during four Quran burnings in 2023 that sparked outrage in Muslim countries, a verdict that reignited debate about the limits of freedom of expression.

The verdict came just days after the man's co-defendant Salwan Momika, a 38-year-old Iraqi, was late Wednesday in an apartment southwest of Stockholm.

The Stockholm district court was to have published its verdict against Momika and 50-year-old Swedish citizen Salwan Najem the following day, but, after Momika's killing, postponed it until Monday.

"There is a wide scope within the framework of freedom of expression to be critical of a religion in a factual and objective debate," judge Goran Lundahl said in a statement.

"At the same time, expressing one's opinion about religion does not give one a free pass to do or say anything and everything without risking offending the group that holds that belief," he said.

The court found Najem, 50, guilty of four counts of "agitation against a national or ethnic group".

He was handed a suspended sentence, which in Sweden means that if he were to commit another crime during a two-year probation period, the court would re-evaluate his sentence.

He was also ordered to pay a fine of 4,000 kronor ($358). Najem has appealed the verdict.

The two men were accused of desecrating the Quran, including by burning it, while making derogatory remarks about Muslims, on two of the occasions outside a Stockholm mosque.

The Swedish government repeatedly criticised the desecrations at the time, but said that freedom of expression was guaranteed under the country's constitution.

"Even if the motive was to criticise the religion of Islam, the actions and conduct exceeded by a clear margin what constitutes a factual debate and criticism. On all occasions, the demonstrations expressed contempt for the Muslim group," the judge said.

Relations between Sweden and several Middle Eastern countries were strained by the pair's protests.

Iraqi protesters in Baghdad twice in July 2023, starting fires within the compound on the second occasion.

Monday's court ruling sparked debate in the Scandinavian country.

Momika meanwhile made virulent remarks about Muslims as a group, comparing them on several occasions to cockroaches among other things, according to the verdict read by AFP.

Najem "is taking the blame for what Momika said," an expert on the issue, Nils Funcke, told public broadcaster SVT.

The ruling means it will become more difficult to criticise religions, "whether it's Islam, Christianity or Judaism," he said.

In a column in paper of reference Dagens Nyheter, journalist Erik Helmerson disagreed, saying the verdict was entirely justified.

"One can totally defend the idea that it should be authorised in Sweden. But there is a law against inciting ethnic hatred, and it would be difficult to find a more clear-cut example of someone breaking it," he wrote.

He recalled that according to the verdict, Momika and Najem during their public appearances accused Muslims of being pedophiles, among other insults.

In August 2023, Sweden's intelligence service Sapo raised its threat level to four on a scale of one to five, saying the Quran burnings had made the country a "prioritised target".

The government has since been examining legal ways to ban public protests where Qurans are desecrated.

Deputy Prime Minister Ebba Busch last week called Momika's murder "a threat to our free democracy", with Prime Minister Ulf Kristersson saying there was "a risk that there is also a link to a foreign power".

Five men were arrested in connection with the murder but have since been released.