The Bulgarian capital of Sofia suffered a series of Allied bombing raids during World War II, from mid 1941 to early 1944. Bulgaria declared war on the United Kingdom and the United States on 13 December 1941. The Southern Italy-based Allied air forces extended the range of their strategic operations to include Bulgaria and other Axis allies in 1943. Raids April 1941 During the invasions of Yugoslavia and of Greece, the Yugoslav and British air forces targeted strategic points in Bulgaria, from which German troops had staged the invasions. On 6 April, Yugoslav Dornier Do 17 aircraft bombed the industrial section of Sofia and Kyustendil. In Sofia, eight people were killed. In the bombing of Kyustendil 58 civilians, two Bulgarian and eight German soldiers were killed and 59 civilians, five Bulgarian and 31 German soldiers were wounded. Between 20:05 and 21:40 on 6 April, the Royal Air Force (RAF) carried out bombing raids over Bulgaria. Bristol Blenheim aircraft bombed Petrich and Haskovo and six Vickers Wellington bombers dropped bombs over Sofia and nearby villages. During the bombing of the capital, 14 buildings were destroyed and three fires were started. Sofia was bombed a second time on 13 April, provoking a large exodus. 14 November 1943 The air raid was carried out on 14 November 1943 by 91 B-25 Mitchell bombers. Forty-seven buildings and structures were destroyed, 59 military personnel were killed and over 128 were injured. 24 November 1943 A new bombing followed on 24 November, this time executed by 60 B-24 Liberator aircraft. 87 buildings in the vicinity of the Central Railway Station were destroyed with 29 being wounded. Bulgarian fighters shot down two bombers for the loss of one aircraft to escorting American fighters. 10 December 1943 The 10 December raid was carried out by 120 aircraft. About 90 bombs were released over the Hadzhi Dimitar, Industrialen, Malashevtsi and Voenna rampa quarters, another 90 hit Vrazhdebna Airport and the nearby villages. 20 December 1943 One of the most destructive raids followed on 20 December, with over 113 buildings being razed to the ground, the belt line being cut off, with 93 people injured. Bulgarian fighter aircraft downed three bombers and seven fighters for the loss of two aircraft, including one destroyed in a suicidal ramming attack by Dimitar Spisarevski which brought down a bomber. 30 December 1943 A day bombing in the Sofia railway junction area was executed