Libya. Rommel underestimates the number of Allied troops at Tobruk (about 30,000) and their determination. German tanks & armoured cars again probe the perimeter in small groups but are repelled. Luftwaffe and artillery bombard Tobruk (3 Stukas shot down over the harbour). Believing the Allies ready to evacuate Tobruk, Rommel also sends columns further East to chase the British into Egypt (his stated goal is the Suez Canal). To prevent this, British prepare blocking positions at Halfaya Pass, near Sollum, Egypt. RAF bombs and strafes German columns moving around Tobruk and towards the frontier with Egypt. British submarine HMS Tetrarch sinks Italian tanker Persiano 55 miles Northeast of Tripoli, Libya.
Greece. Leibstandarte SS infantry overrun British and Australian troops South of Vevi. With the Aliakmon Line unhinged, Allied forces to the East pull back to a line inland from Mount Olympus to block both the valley from Vevi and the coastal route from Salonika. British anti-aircraft cruiser HMS Coventry, destroyers HMS Decoy & HMS Encounter and troopship Glenroy evacuate a battalion of troops, 1000 tons of stores and 40 vehicles from Greek island of Lesbos in the Aegean Sea near Salonika.
Yugoslavia. Hungary joins the German/Italian invasion, to take a share of the spoils. In the evening, Serbian capital of Belgrade surrenders to German troops converging from 3 directions. German Ju87 Stukas dive-bomb 4 Yugoslav WWI-era river monitors on the River Danube (3 shot down by anti-aircraft guns on the monitors). Drava is destroyed by a bomb down the funnel (54 crew killed, 13 survivors) while Morava, Sava & Vardar are scuttled to avoid capture by the advancing Germans.
At 5.09 AM 100 miles Southwest of Freetown, Sierra Leone, U-124 sinks another steamer carrying grain from Argentina to Britain, British SS St. Helena (all 36 crew, 2 gunners and 3 passengers picked up by destroyer HMS Wishart and landed at Freetown). 920 miles Southwest of Freetown, German armed merchant cruiser Kormoran sinks Greek steamer SS Nicolaos D. L. carrying Oregon pine from Canada to Durban, South Africa (all 38 crew taken prisoner).