"It has already been discovered that all the anonymous calls had been made from abroad," the source said.
Earlier in the day, security forces checked all nine Moscow railway stations after anonymous phone calls. Despite the alleged bomb threats, the railway stations have not been evacuated and the traffic timetable remained unchanged.
Last year, Moscow faced a wave of the so-called telephone terrorism with some 250,000 having been evacuated from various facilities in the Russian capital.
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