On March 23 Cronstedt parleyed with Russian representatives on the island Lonnan, where Russians demanded the surrender of the fortress. After the Swedish refusal to comply, the Russians started another barrage against the fortress on 25 March which lasted until 1 April. The Russian surrender demand was repeated on 2 April. The Russians resorted to cunning psychological warfare to convince the officers in the fortress to surrender. Former Swedish subject Johan Samuel Hagelström received special commendation from the Tsar for his actions in getting Sveaborg to surrender. Certain officers' wives who lived in Helsingfors and were allowed and encouraged by the Russians to visit the husbands in Sveaborg also played their parts. Perhaps the most important person in the Russian efforts to use cunning to force a surrender was the trusted advisor of Cronstedt, Colonel Fredrik Adolf Jägerhorn.