Atlantic

U.S. naval units begin patrolling the Atlantic eastward to 26 degrees east longitude and southward to 20 degrees north latitude.

Axis Diplomacy

Hitler and Hungarian leader Adm Horthy confer and dine in the Führer's train near Graz, Austria. Horthy lavishes praise on the Führer, but Hitler refuses to be drawn into promising major territorial concessions in return for Hungarian participation in Operation Barbarossa.

Greece

The Germans mount a large attack against the British lines at Thermopylae but they are held off. The British have been reinforced by Greek detachments who refuse to surrender. The position has largely served its delaying function and during the night the defending troops fall back, leaving a further rearguard at Thebes. During the night the main evacuation begins, with 11,000 men being taken off.

German paratroopers occupy the islands of Limnos, Thasos and Samothrace in the northeastern Aegean. The Italian 9th Army takes the Perati bridge and joins up with the German forces.

Bulgaria declares war on Greece and Yugoslavia. Bulgarian troops begin occupyin territory in western Thrace, which is already under German control.

Iraq

The British garrison in Iraq is reinforced by the despatch of additional units.

Mediterranean

• The evacuation of British and Commonwealth troops from Greece begins in Operation Demon. From now until 29 April 51,000 troops are transported to Crete and Egypt. German aircraft sink the destroyers Diamond and Wryneck and 4 transports.
• German aircraft sink a large number of Greek ships. Included in the sinkings are the hospital ship Andros (2068t) off Loutraki, Gulf of Corinth, the steamer Hellas (2295t) at Piraeus, the steamer Kehrea (1968t) in the Bay of Frangolimano, the steamer Kyriaki (5528t) at Suda Bay, the steamer Petros (634t) at Porto Heli, the steamer Popi S. (2083t) at Milos Island, the steamer Pylaros (932t) at Galaxeidion, and the steamer Point Judith (4810t) at Kythnos Island.

Singapore

Australian reinforcements arrive to aid in land and sea defense preparations.

United States, Politics

Roosevelt formally orders US warships to report the movements of German warships west of Iceland. This is happening unofficially already. The information is usually passed one way or another to the British.