Air Operations, Carolines

During the night, VII Bomber Command B-24s attack the Truk Atoll.

Air Operations, CBI

• More than 20 10th Air Force P-40s attack targets in the Myitkyina area.
• 19 P-40s attack numerous targets while conducting sweeps over northern Burma.

• 14th Air Force P-40s support Chinese Army ground troops on the Salween River battle front.

• 14th Air Force P-40 fighter-bombers attack rail targets of opportunity in northeastern French Indochina.

• 10th Air Force B-25s airlift ammunition to Imphal.

Air Operations, Europe

• 259 aircraft of Nos. 1, 4, 5, 6 and 8 Groups are sent to bomb 4 gun positions. In this total are 125 Lancasters, 118 Halifaxes and 16 Mosquitos.
• 3 of the targets are deception targets in the Pas de Calais, but the fourth is at Maisy in Normandy, which will become known as Omaha and Utah beaches where American troops will land in 36 hours' time. Maisy is cloud-covered and can only be marked by Oboe skymarkers and the area is bombed by 52 Lancasters of No. 5 Group. 2 of the targets in the Pas de Calais are also covered in clouds, but the position at Calais itself is clear and accurately marked by the Mosquitos and well-bombed by Halifaxes and Lancasters of No. 6 Group.
• No aircraft are lost on these operations.

• 20 Mosquitos are sent to Cologne, 6 to Argentan, 4 Halifaxes and 3 Lancasters lay mines from the Scheldt to Dunkirk, 17 aircraft are on Resistance operations, and there are 6 Serrate patrols and 4 RCM sorties.
• There are no losses.

Air Operations, New Guinea

• V Bomber Command B-24s attack the Borokoe airfield on Biak and the Namber airfield on Noemfoor, and the mouth of the Orai River.
• 3rd Light Bomb Group A-20s attack the airfield at Babo.
• A-20s attack Wewak, port facilities at Manokwari, and shipping near Geelvink Bay.
• V Fighter Command fighter-bombers attack coastal targets at Hansa Bay.
• Planned attacks by V Bomber Command B-24s against Japanese Army positions on Biak Island are thwarted by bad weather.
• At 1740 hours, 6 G4M 'Betty' bombers and 28 A6M Zeros based at the airfield at Sorong attack a US-Australian surface battle force 120 miles east of Biak. One USN cruiser is slightly damaged.
• During the evening, 2 Japanese bombers attack Allied aircraft on the ground at Wakde Airdrome and cause very heavy damage.
• A 475th Fighter Group P-38 downs a Ki-43 'Oscar' fighter near Moisnneom Island at 1040 hours.
• 348th Fighter Group P-48s down a B5N 'Kate' torpedo bomber and 3 A6M Zeros near Biak Island between 1740 and 1755 hours.

Battle of the Atlantic

An American Navy antisubmarine force captures a German submarine (U-505) 150 miles off the coast of Rio de Oro (Spanish Sahara), Africa. It is the first enemy ship captured by a US naval boarding party since 1814. The submarine surfaced when attacked, but the crew abandoned it when it started to sink. American seamen boarded and salvaged it, and the submarine is towed to the US. The antisubmarine force responsible for this capture include the escort carrier Guadalcanal (CVE-60) and the destroyer escorts Pillsbury (DE-133), Pope (DE-134), Flaherty (DE-135), Chatelain (DE-149) and Jenks (DE-665).

Burma-China-India

On the Salween River front, Chinese artillery silences the Japanese batteries shelling Huei-jen bridge. The Chinese 87th and 88th Divs converge on Lungling. The Chinese 28th Div, only recently formed, occupies the village of Lameng and engages the Japanese garrison of Sung Shan. In the Imphal area the 20th Indian Div advances north toward Ukhrul to join up with the 7th Indian Div, which is coming south from Kohima. The Japanese 15th Div is in danger of being trapped northeast of Imphal.

Italy

As the last German rearguards are leaving the capital, Gen Clark's first units enter the suburbs in the south. At 7:15p.m. units of the US 88th Div reach the Piazza Venezia. MAAF fighter-bombers decimate German columns retreating north along Highways 1, 2 and 3, destroying or damanging 1,000 vehicles. During the night Wellingtons and Liberators plaster Highways 3 and 4 with heavy bombs.

Rome's population greets the Allies enthusiastically after a length period in which the Germans defended southern Italy with incredible determination to delay the inevitable capture of the first Axis capital to fall. Hitler orders the Italian capital evacuated, according to Radio Berlin, to avoid putting the city 'under the peril of destruction'. With the exception of rail yards bombed by the Allies, Rome escapes the war relatively unscathed.

New Guinea

Preparations begin for the invasion of Noemfoor, or Numfoor Island, west of Biak, between Biak and the peninsula that forms the northwest extremity of New Guinea. There are 3 airfields on Numfoor that can be uses as jumping-off places against the central Pacific and also to control the sea routes west of Biak.

Pacific

The Japanese transport No. 128 is sunk by US Army aircraft in the Philippine Sea.

Operation OVERLORD

The date for Operation OVERLORD, the landing in Normandy, where the enemy least expect it, was fixed on May 8 by Eisenhower, and confirmed on May 17, as June 5 or 6, or at the very latest June 7. These are the only dates on which he can rely on 2 conditions essential to success. The first, the moon will rise late and help the landing by the parachutists and airborne troops - about 22,000 men of the American 101st and 82nd Divs and the British 6th Div. The second, low tide will be at dawn and will uncover all the obstacles and mines that Rommel has had put down so that they can be most easily neutralized by specialists going ashore ahead of the first wave, blowing up the mines and destroying the obstructions. The next low tide will come just before sunset, and then the second wave will land. These 3 days are the only ones in the whole month when the meteorological requirements will be right. Although the tides will be favorable again on June 19, by then the moon will be wrong and the airborne forces would have to attack in complete darkness. If the June dates are missed it will be necessary to wait until July, but so long a delay, as Eisenhower says later, is 'too painful to contemplate.' Eisenhower decides first that the landing shall take place on June 5, but on June 4, a Sunday and the day Rommel leaves for Germany, he orders a 24 hours' delay because of bad weather.

The convoys for the invasion are already at sea, but because of bad weather expected on June 5, they turn back to wait. Late in the evening Eisenhower decides, after consulting with the meteorological staff headed by Air-Marshal I. N. Stagg of the RAF, that the invasion can take place on June 6 when a break in the weather is expected. He says, 'I don't like it but I don't see what else I can to. I am absolutely convinced that the order must be given.' It has long been decided that the first landings must be at dawn when there is a low tide. This should allow the engineering teams to work their way up the beach to the high-water mark clearing visible obstacles. These tidal conditions only occur on about 3 days every fortnight. Also desirable is for the moon to rise late to aid the airborne troops. These conditions pertain on June 5 and 6 and less ideally June 7. If the invasion does not take place then, the tides will be right about June 20 but the combination of moon and tides not until July. Eisenhower, therefore, has had to take a very difficult decision because any postponement would be bound to affect the troops morale; to give the Germans more time to improve their defenses; to upset relations with the Russians; and almost certainly jeopardize the security of the plan (for one thing the deception operation has been scheduled in line with the June 5 date).

The bad weather has helped in putting the Germans off their guard. Rommel has decided to take the opportunity to go to Germany for his wife's birthday on June 6 and to try to persuade Hitler to adopt his strategic ideas which include, among other things, strengthening the Normandy defenses. Other more junior commanders are also away from their posts - many at a training exercise at Rennes in Brittany.

Images from June 4, 1944

Liberation of Rome, 4 June 1944

Waves of Cheers Greet the Allied Tanks Rumbling through the Crowd-lined Streets of Rome, 4 June 1944

At a Coastal Forces Base, HMS Hornet and Gosport, 4 June 1944

4 June 1944 - the Liberation of Rome

American M4 Sherman Tanks and Jeeps Enter Rome Italy June 1944

Maj Gen Gale Talking to Airborne Troops at Their Transit Camp, 4 June 1944

German Submarine U-505 Being Captured by Sailors from USS Guadalcanal, 4 June 1944

A Church Service On Board a US Landing Craft, 4 June 1944

The Highland Light Infantry of Canada load onto Landing Craft, Infantry, Large at Southhampton, 4 June 1944.

Canadians Loading onto a Landing Craft

5th Army infantry patrol on M10 tank destroyer and jeeps cross bridge in Rome, Italy. 4 June 1944. Jeep of a two-star general is parked to the right.

5th Army Patrol in Rome

A-20 Havoc Attacking Targets in Occupied Europe, 4 June 1944