Protests in Stockholm on Saturday against Turkey and Sweden's bid to join NATO, including the burning of a copy of the Koran, sharply heightened tensions with Turkey at a time when the Nordic country needs Ankara's backing to gain entry to the military alliance.

"We condemn in the strongest possible terms the vile attack on our holy book ... Permitting this anti-Islam act, which targets Muslims and insults our sacred values, under the guise of freedom of expression is completely unacceptable,” the Turkish Foreign Ministry said.

Its statement was issued after an anti-immigrant politician from the far-right fringe burned a copy of the Koran near the Turkish Embassy. The Turkish ministry urged Sweden to take necessary actions against the perpetrators and invited all countries to take concrete steps against Islamophobia.

A separate protest took place in the city supporting Kurds and against Sweden's bid to join NATO. A group of pro-Turkish demonstrators also held a rally outside the embassy. All three events had police permits.

Swedish Foreign Minister Tobias Billstrom said that Islamophobic provocations were appalling.

"Sweden has a far-reaching freedom of expression, but it does not imply that the Swedish Government, or myself, support the opinions expressed,” Billstrom said on Twitter.

The Koran-burning was carried out by Rasmus Paludan, leader of Danish far-right political party Hard Line. Paludan, who also has Swedish citizenship, has held a number of demonstrations in the past where he has burned the Koran.

Paludan could not immediately be reached by email for a comment. In the permit he obtained from police, it says his protest was held against Islam and what it called Turkish President Tayyip Erdogan's attempt to influence freedom of expression in Sweden.

Several Arab countries including Saudi Arabia, Jordan and Kuwait denounced the Koran-burning.“Saudi Arabia calls for spreading the values of dialogue, tolerance, and coexistence, and rejects hatred and extremism,” the Saudi Foreign Ministry said in a statement.

Sweden and Finland applied last year to join NATO following Russia's invasion of Ukraine but all 30 member states must approve their bids. Turkey has said Sweden in particular must first take a clearer stance against what it sees as terrorists, mainly Kurdish militants and a group it blames for a 2016 coup attempt.

At the demonstration to protest Sweden's NATO bid and to show support for Kurds, speakers stood in front of a large red banner reading“We are all PKK”, referring to the Kurdistan Workers Party that is outlawed in Turkey, Sweden, and the United States among other countries, and addressed several hundred pro-Kurdish and left-wing supporters.

"We will continue our opposition to the Swedish NATO application,” Thomas Pettersson, spokesperson for Alliance Against NATO and one of organizers of the demonstration, told Reuters.

Police said the situation was calm at all three demonstrations.

In Istanbul, people in a group of around 200 protesters set fire to a Swedish flag in front of the Swedish consulate in response to the burning of the Koran.

Swedish minister's visit cancelled

Earlier on Saturday, Turkey said that due to lack of measures to restrict protests, it had cancelled a planned visit to Ankara by the Swedish defence minister.

Jonson said separately that he and Akar had met on Friday during a gathering of Western allies in Germany and had decided to postpone the planned meeting.

Turkish Defence Minister Hulusi Akar said he had discussed with Erdogan the lack of measures to restrict protests in Sweden against Turkey and had conveyed Ankara's reaction to Jonson on the sidelines of a meeting of the Ukraine Defence Contact Group.

"It is unacceptable not to make a move or react to these (protests). The necessary things needed to be done, measures should have been taken,” Akar said, according to a statement by Turkish Defence Ministry.

Turkey's Foreign Ministry had already summoned Sweden's ambassador on Friday over the planned protests.

Finland and Sweden signed a three-way agreement with Turkey in 2022 aimed at overcoming Ankara's objections to their membership of NATO. Sweden says it has fulfilled its part of the memorandum but Turkey is demanding more, including the extradition of 130 people it deems to be terrorists.