 Complete the following phrase:  The Il-28 was widely exported, serving in the air arms of some 20 nations ranging from the Warsaw Pact to various Middle-Eastern and African air forces. Egypt was an early customer, and targeting Egyptian Il-28s on the ground was a priority for the Royal Air Force during the Suez Crisis and later by the Israeli Air Force during the Six-Day War, and Yom Kippur War. The Soviet Union was in the process of providing the type for local assembly in Cuba when this was halted by the Cuban Missile Crisis, after which Nikita Khrushchev agreed to remove them. The type also saw limited use in Vietnam and with the Afghan forces in Afghanistan. Four ex-Egyptian and two ex-Soviet Il-28s all with Egyptian crews were operated by the Nigerian Air Force in the Biafra Wars. Yemeni Il-28s took part in the 