The memorial will eventually be moved to the Pier Head
A memorial plaque has been unveiled in memory of more than 800 people who were killed when a liner was torpedoed by a German U-boat off the Irish coast.
The Arandora Star was carrying Italian, Austrian and German internees and prisoners of war from Liverpool to Newfoundland in 1940 when it was hit.
Relatives of those who died were invited to take part in the special service on a Mersey ferry.
The memorial is at Our Lady and St Nicholas' Church in Chapel Street.
It will eventually be moved to the Pier Head close to Liverpool's Three Graces on the waterfront after regeneration work is completed.
Some of the people killed held British nationality and had been born or settled in the country but had Italian, Austrian or German surnames.
There were also 868 survivors of the disaster. They managed to scramble into lifeboats before being rescued by a Canadian destroyer.
It is hoped the memorial will also provide a focal point for them to remember the friends and relatives they lost.
Liverpool's Lord Mayor Steve Rotheram said: "It is very appropriate that in the European Capital of Culture year, we remember the peace that Europe has enjoyed through the founding of the European Union.
"We should acknowledge the past; commemorate those who have had no commemoration, while seeking reconciliation and promoting greater understanding."
Honorary Italian Consul on Merseyside Nunzia Bertali said: "The torpedoing of the Arandora Star was a tragedy.
"I hope this memorial will make sure that we learn from the mistakes of the past."