These mainly involved sabotage of the refineries by Special Operations Executive (SOE) agents and Romanian collaborators[4] and blocking the Danube oil exports.

Another attempt to destroy the oilfields with a company of Royal Engineers also failed as the fall of France led King Carol II to reconsider the sabotage plan.

This plan was created by Air chief marshal Cyril Newall and called for the use of five bomber squadrons and a four-month campaign in which 25–30% of the Ploiești refineries could be destroyed.

[7][10] In early 1943, at the Casablanca Conference, Churchill once again reiterated the importance of attacking Romania's oil refineries and disrupting the German war effort.

Due to a lack of resources, planning was postponed until April 1943, when General Henry H. Arnold commissioned his staff to resume their development.

[7] Code-named Operation Tidal Wave, the attack on 1 August 1943 consisted of a large-scale low-altitude air raid over Romanian oil refineries at Ploiești by 178 unescorted B-24 Liberators.

After General Spaatz' plan was authorized to start the campaign in Romania in March, the Fifteenth Air Force began raids on 4 April 1944, initially targeting rail infrastructure while also inadvertently hitting some refineries as well.

[17] Smoke screens deployed over the city proved to be very effective, and the first missions failed to deal substantial damage to the refineries.

[18][19] The campaign was called off on 19 August due to Soviet demands as the Red Army was about to launch a major offensive against Romania.

[21] Code-named "Gardening" operations, the raids were conducted by Liberator and Wellington bombers and aimed to disrupt the oil transport on the river.

[24] On 2/3 July 1944, a bomber force of 31 Wellingtons, 9 Liberators, and 8 Halifaxes was dispatched to attack oil storage tanks in Bucharest.

[20] Unlike the raids over Germany, the British and Americans avoided targeting civilian objectives in Romania as it was known that Romanian public opinion was against continuing the war.

Only propaganda leaflets were to be dropped in residential areas, while low altitude raids on the Danube also forbade using machine guns on settlements along the river.

Initially located in the barracks of the 6th Guard Regiment "Mihai Viteazul",[25] it was later moved to the Normal School on St. Ecaterina street.

[32] All Allied airmen who were taken prisoner during the air campaign were repatriated by airlift to Italy during Operation Reunion after the 1944 Romanian coup d'état.

[33] Although not directly engaging Romanian ground troops, the Western Allies had supplied military equipment to the Red Army via Lend-Lease.

[34][35] A proposal for an Allied intervention in Romania was also made in October 1943 through the Romanian vice-consul in Istanbul to the SOE by the generals conspiring in the future coup against Antonescu.

The generals in charge of the plan, Constantin Nicolescu and Gheorghe Potopeanu [ro], insisted on a token force of one or two thousand British paratroopers be sent to Romania to accept the unconditional surrender of the Romanian Army, thus avoiding a direct capitulation to the Soviets.