The U.S. operator of the popular "Pokemon Go" smartphone game stopped appearances by Lapras, a rare plesiosaur-like monster, in the Tohoku region out of safety concerns following Tuesday's major earthquake and subsequent tsunami warnings.

The official "Pokemon Go" Twitter account made the announcement in the afternoon after the magnitude-7.4 quake jolted Fukushima, Miyagi and other prefectures, causing tsunami, including one that made landfall near the wrecked Fukushima No. 1 nuclear plant.

The U.S.-based game maker Niantic Inc. had announced Nov. 11 that Lapras, a rare character in the augmented-reality game, would start popping up more in the coastal areas of Iwate, Miyagi and Fukushima prefectures, to help draw more tourists to the region ravaged by tsunami following the March 2011 Great East Japan Earthquake. The character's appearances were to have lasted until Wednesday.

It is believed the company made the decision out of fear that "Pokemon Go" enthusiasts might place themselves in harm's way searching for the rare character.

"In light of the current situation in coastal areas of Tohoku, we will wrap up the appearances of Lapras as of today," cutting short the project by a day, the official "Pokemon Go" account tweeted.

"We seek the understanding and cooperation of everyone. We will continue to help with the reconstruction of Tohoku."

Tuesday's quake triggered tsunami of 1.4 meters in the port of Sendai, 1 meter near the Fukushima No. 1 nuclear plant and 90 cm in Soma, Fukushima Prefecture. All tsunami warnings and advisories were lifted by 12:50 p.m.