The firebombing campaign against major cities ended in June. On the first day of the month 521 B-29s escorted by 148 P-51s were dispatched in a daylight raid against Osaka. While en route to the city the Mustangs flew through thick clouds, and 27 of the fighters were destroyed in collisions. Nevertheless, 458 heavy bombers and 27 P-51s reached the city and the bombardment killed 3,960 Japanese and destroyed of buildings. On 5 June 473 B-29s struck Kobe by day and destroyed of buildings for the loss of 11 bombers. A force of 409 B-29s attacked Osaka again on 7 June; during this attack of buildings were burnt out and the Americans did not suffer any losses. Osaka was bombed for the fourth time in the month on 15 June when 444 B-29s destroyed of the city and another of nearby Amagasaki; 300,000 houses were destroyed in Osaka. This attack marked the end of the first phase of XXI Bomber Command's attack on Japan's cities. During May and June the bombers had destroyed much of the country's six largest cities, killing between 112,000 and 126,762 people and rendering millions homeless. The widespread destruction and high number of casualties from these raids caused many Japanese to realize that their country's military was no longer able to defend the home islands. American losses were low compared to Japanese casualties; 136 B-29s were downed during the campaign. In Tokyo, Osaka, Nagoya, Yokohama, Kobe, and Kawasaki, "over 126,762 people were killed ... and a million and a half dwellings and over of urban space were destroyed." In Tokyo, Osaka and Nagoya, "the areas leveled (almost ) exceeded the areas destroyed in all German cities by both the American and British air forces (approximately )."