These revisions followed Soviet demands closely. When Britain tried to add some of their own (fearing that the provisions were there only to augment the Soviet air-defences) they were opposed by the Soviets. The revisions were again revised in 1963 and Finland was allowed to buy guided missiles and a few bombers that were used as target-tugs. The FAF also used a loop-hole to strengthen its capabilities by purchasing large numbers of two-seater aircraft, which counted as trainer aircraft and were not included in the revisions. These aircraft could have secondary roles.