Sweden announced a new crackdown on terrorism on Thursday as it struggles to persuade Turkey it has a tough enough stance to join Nato.
Anyone who takes part in an extremist group's activities would be punishable under a new law, even if there is no connection to a specific terrorist crime, and prison sentences would also be increased.
Justice Minister Gunnar Strommer said the threat level had increased after the burning of a Quran by far-right figure Rasmus Paludan in Stockholm.
That incident put further strain on relations with Turkey, which said Sweden could not join Nato if it condones burning the Quran.
Turkey has demanded for months that Sweden and Finland take a tougher line on terrorism, especially on Kurdish militants, before it approves their Nato applications.
Turkish President Recep Tayyip Erdogan, who has elections coming up in May, has indicated publicly and privately that he is happier with Finland's efforts than Sweden's.
A poll suggested on Thursday that people in Finland would support joining Nato alone if Turkey does not relent in its objections to Sweden.
Asked "whether Finland should wait for Sweden", only 28 per cent of Finns said it should, while 53 per cent said it should not, according to polling company Taloustutkimus.
Finland's government has so far resisted that idea, saying the two countries share a common security landscape and should join together.
Hungary, the only other Nato member yet to approve Sweden and Finland's applications, this week said Sweden should "act differently" if it wants to clinch Turkish support.
Sweden and Finland turned a page on decades of military non-alignment after the invasion of Ukraine by Russia, which has a 1,340-kilometre land border with Finland.
Swedish Prime Minister Ulf Kristersson was to hold talks with his Finnish counterpart Sanna Marin in Stockholm later on Thursday.
The two countries promised Turkey they would step up their counter-terrorism efforts in a three-way agreement signed in June.
The new Swedish bill would "considerably enhance" Sweden's counter-terrorism powers, Mr Strommer said, although he stopped short of saying it could influence Turkey's thinking.
"This is a far-reaching law that covers basically all cases of participation in these kinds of activities,” he said.
“The current law requires that an activity must be connected to a certain act of terrorism to be illegal, but this law is focused on participation, which makes it far broader and more forceful.”
Mr Strommer said the Quran-burning incident had made Sweden a potential terrorist target and led to "clearer and stronger rhetoric".
Germany on Wednesday closed its consulate in Istanbul for three days over security fears. Turkish Interior Minister Suleyman Soylu condemned such travel warnings on Thursday, saying they would damage tourism.
