Nigerian police said one of the kidnappers had called to make the ransom bid.
Three Ukrainians, two Indians and a Russian were seized from Bumi Armada's 2,150-gt anchor-handler Armada Tuah 101 (built 2007) on Monday.
Ukraine's foreign ministry said on 20 February that its citizens had been freed, but Russia said the next day that all six were still in captivity.
