Germany: Bethmann denounces Italy in Reichstag. German reply puts all Lusitania responsibility on Britain.
Germany: First Reichstag annexation debate.
Ceylon: Riots (until June 5).
Artois: French 53rd Division advance in savage hand-to-hand fighting in the ‘Labyrinth’ north of Arras (until June 1).
Italian Front: Austrian Fort Lusern (Trento) nearly surrenders but fire from neighbours stiffens it. Italians vainly attack Sleme and Mrzli massifs south of Mt Nero (until June 4); Modena Brigade loses 1,237 casualties.