Finnish police have arrested two more suspects over last week's stabbings that killed two people and wounded eight in the south-western city of Turku.
Officers said they arrested two men on suspicion "of preparation of an offence to be committed with terrorist intent".
On Tuesday, a regional court ordered that an 18-year-old Moroccan asylum-seeker be detained on suspicion of terrorist crimes, including two counts of murder and eight counts of attempted murder.
Three alleged accomplices also were ordered to be held on suspicion they helped plan the attack.
The main suspect, who has acknowledged the stabbings but denies murder, was named as Abderrahman Mechkah, although police said they believe he is using a false identity.
Investigators have said they are exploring possible links to last week's extremist attacks in Spain.
Detective Superintendent Markus Laine told national broadcaster YLE on Wednesday that there were signs Mechkah had become "radicalised" but declined to give any details.
Mechkah was shot in the thigh by police during the knife rampage in Turku, 170 kilometres (105 miles) west of the capital Helsinki, and was treated for his wounds at a local hospital before a planned move to a prison hospital, police said.
The nationality of the new suspects was not clear, police said, because they gave contradicting information.
They told Finnish officials they were Algerian citizens but had earlier told Swedish authorities that they were from Morocco. It was unclear when they were in Sweden.
The main suspect arrived in Finland last year, but his application for asylum was denied, police said.
Earlier, the German Interior Ministry said the man entered Germany at the end of 2015, leaving there in early 2016.
He did not apply for asylum in Germany, the ministry said.
Investigators and the main suspect's lawyer Kaarle Gummerus have said they were not aware of a motive for the attack, in which most of the victims were women.