An Iranian frigate entered Estonian territorial waters on Friday without prior authorisation, but promptly left after being contacted by Tallinn, ERR News reported on Sunday.
"Iranian frigate IRIS Sahand, on its way to Saint Petersburg, entered Estonian territorial waters without permission northwest of Osmussaar a little after 22:00 yesterday," Andra Jundas, press representative for Estonia's Police and Border Guard Board (PPA), said on Saturday.
Foreign ships are allowed to transit Estonian territorial waters, but have to request permission 48 hours in advance, which the Iranian ships failed to do.
Last week, the biggest Iranian military ship, IRIN Mekran, accompanied by IRIS Sahand entered the Baltic Sea.
CNN reported earlier that the Pentagon has been monitoring the two Iranian ships due to concerns that they would deliver Iranian weapons to Venezuela. The ships later changed course and entered the Baltic Sea on their way to Navy Day events in Russia’s St Petersburg.