Four young men were detained early Tuesday on suspicion of an attempted arson attack on the Turkish embassy in Helsinki, police said.
Police said the four were being questioned about the alleged attack but declined further comment when contacted by Deutsche Presse-Agentur dpa.
Finnish media reported that the small fire was likely caused by flammable fluid contained in a bottle thrown against the embassy door.
Police have not ruled out a political motive. A protest was held on Monday near the embassy in support of jailed Kurdish separatist leader Abdullah Ocalan.

Shares fell 2.1 per cent Friday on the Seoul stock exchange on general recession fears. South Korea's won dropped against the dollar.
When the Spirit rover landed on Mars five years ago, no one expected it or its sister rover Opportunity to make it to their first birthdays, let alone their fifth.
Amelie Mauresmo fell victim to a leg injury after less than half an hour on court Friday to hand over a 4-0 victory which put French compatriot Marion Bartoli into the final of the Brisbane International.
Mumbai-based movie Slumdog Millionaire won five prizes Thursday night at the Critics Choice Awards, cementing its position as a surprise favourite just as the Oscar season moves into high gear.
After the Taipei Zoo received two giant pandas from China, another Taiwan zoo said Friday it is seeking to receive a pair of pandas from China.