BERLIN — German investigators announced Monday that they seized cocaine worth 2.6 billion euros ($2.78 billion) from several container ships and arrested seven people in what they called the biggest ever cocaine find in the country.

Prosecutors in the western city of Duesseldorf said they confiscated the 35.5 metric tons (39 U.S. tons) of cocaine last year following a tip from Colombian authorities. They added they found 25 tons of cocaine in the port of the northern city of Hamburg,…