Police in the South Korean capital Seoul were put on high alert following a series of alleged bomb threats, sent via emails, to the country’s top court and a diplomatic mission.

However, no trace of any bomb material was found after police searched locations mentioned in at least five emails purportedly sent from Japan, Seoul-based Yonhap News reported Thursday.

"High-powered bombs with needles had been planted at the Japanese Embassy, the Supreme Court and city halls across the country, and would go off from 3:34 p.m. Friday (0634GMT) to 2:07 p.m. Saturday (0507GMT)," read the emails sent over the past 10 days.

South Korean police were working in cooperation with their Japanese counterparts to identify the origin of the emails, which were signed by a Japanese lawyer.

The lawyer, however, has said his name was being misused.

A similar email was sent to the South Korean Embassy in the Japanese capital Tokyo where police have beefed up security since Monday.

The Yonhap report added that a series of bomb threats via email in recent weeks, targeting schools and government offices across the nation, sent police searching the area with special forces and sniffer dogs and people fleeing for safety.