Battle of Keren, Eritrea. At 4.30 AM, tanks and infantry push through the Dongolaas Gorge along the newly repaired road and capture the heights beyond, which dominate the Gorge and the town of Keren. 3,000 Italian troops in the hills around the Gorge gradually surrender. Keren is taken without a fight at 10 AM and Italian troops are pursued as they retreat towards the capital Asmara. Allied casualties are 536 killed & 3,229 wounded, while Italy loses 6,500 killed, missing & wounded.
As the Italian Fleet is known to be at sea from Ultra intercepts, Admiral Cunningham’s Mediterranean fleet (battleships HMS Warspite, Barham & Valiant, aircraft carrier HMS Formidable & 9 destroyers) leaves Alexandria, Egypt. In addition, 4 cruisers & 4 destroyers leave Piraeus, Greece. A Sunderland flying boat is sent out ‘spotting’ as a pretext. The Italian warships are located at noon without the promised Luftwaffe air cover.
Coup d’etat in Yugoslavia. Crowds in Belgrade spit at the German Ambassador. Inspired by anti-Nazi sentiments and vague British promises of military help, Air Force General Dušan Simović seizes power (deposing Prime Minister Dragiša Cvetković on his return from Vienna). Regent of Yugoslavia, Prince Paul is replaced with 17 year-old heir to the throne King Peter II (he and new Prime Minister Simović intend to renounce the Tripartite Pact). On hearing the news, Hitler orders Yugoslavia to be invaded along with Greece, diverting 29 divisions and 2000 aircraft to the Balkans from the planned invasion of USSR (Operation Barbarosa).
At 1.50 PM 400 miles Southwest of Iceland, U-98 sinks British SS Koranton (all 34 hands lost). In the same area, Oberleutnant zur See Helmut Pöttgen falls overboard from U-46 and is lost.