Bullet and commuter trains were suspended for around three hours Tuesday as personnel from the Ground Self-Defense Force detonated a wartime antiaircraft shell found at a northern Tokyo construction site.

The GSDF bomb squad destroyed the wartime ordnance at 11:56 a.m. at the site where it was found in March near Kaminakazato Station on the JR Keihin Tohoku Line in Kita Ward.

An estimated 90,000 passengers were effected by the suspension of train services.

Kita Ward Mayor Yosouta Hanakawa declared the area safe at 1:58 p.m., lifting an exclusion zone of 100 meters around the site. No residents had to be evacuated because there were no dwellings within the designated zone, the ward said.

The shell, measuring 40 cm long and 8.8 cm in diameter, is believed to have belonged to the Imperial Japanese Army. It was not clear how old the explosive was. It was found in March when the construction site was being checked for buried cultural assets.

A government office complex is to be built on the site.

East Japan Railway Co. said it halted 150 train runs, including on the Tohoku Shinkansen Line between Tokyo and Omiya stations and the Keihin Tohoku Line between Higashi Jujo and Shinagawa stations, from around 11 a.m. to about 2 p.m.

“We successfully completed the removal of the shell,” Toshihito Takahashi, the GSDF officer who led the detonation work, told reporters afterward. The GSDF team began its preparations at 6:20 a.m.

JR East had asked that the detonation take place at night so the morning commuting train schedule was not disrupted, but Kita Ward and the GSDF decided to deal with it during the day for safety reasons.

Information from Kyodo added