Soviet conventional forces greatly outnumbered the West's, however, and United States strategic nuclear strike plans were developed accordingly. While the United States was the only nation with the atomic bomb, in 1946 it had only 17 Silverplate B-29 bombers and 11 atomic bombs. Many early American war plans were based on using hundreds of nonexisting weapons; for example, an autumn 1945 plan envisioned using 196 atomic bombs on Soviet industrial targets, but SAC could not deliver such quantities until 1952. The bombs were of the Mark 3 type, weighing five tons and requiring 39 men two days to assemble. The press reported that "atomic-capable" B-29s were deployed to Britain in mid-1948 during the Berlin Blockade, by which time the US possessed about 50 atomic weapons. The Soviets likely knew through espionage, however, that none of the aircraft was a Silverplate; rather, they would have been used as part of plan DOUBLEQUICK, involving World War II-like sustained conventional bombing raids on Soviet air bases in Eastern Europe. Other than increasing its anti-aircraft defenses, the Soviets did not change its military preparations in any way during the blockade, unlike the reaction in the West. Although the Soviets launched an intensive public relations effort in 1949, aided by sympathetic Western European fellow travelers, to oppose the formation of NATO, the new alliance's military strength was so weak that the Politburo did not bother to discuss it for six months after its formation.