USA DECLARES WAR ON GERMANY at 1300 hours, (House so votes 373 to 50) and seizes 87 German ships in her ports (14 Austrian ships seized on April 9).
France: President Poincare and generals meet in train at Compiegne to reconsider offensive. Nivelle threatens to resign, but given approval provided attack called off after 48 hours, if expected gains not forthcoming. 5,350 guns now bombarding.
Western Front: Mannock posted to No 40 Squadron. 5 Sopwith Pups of No 3 (Naval) Squadron destroy all of 4 Halberstadt fighters.