Adriatic: Austrian U11 alias German coastal submarine UB15 (Heimburg) surprises and sinks Italian submarine Medusa.
North Cameroons: German Fort Garua surrenders for next day: river flood bars mutinous garrison’s escape; 249 PoWs, 4 guns and 10 MGs.
Russia: Anti-German riots in Moscow until June 12. Interior Minister Maklakov replaced by Prince Shcherbatov.
Britain: Commons votes £250 millions war credit, war costing £2.66 millions per day since April 1, 1915.