An official breaks the news of a grenade having been planted at a mausoleum in a northern area of the Iranian capital Tehran.

People working at a mausoleum called Imamzadeh Saleh -- located at Tajrish Square -- on Tuesday night found a grenade that had been planted in a trash can in the women's restroom, the Fars news agency quoted the head of the Tehran section of the Charity Organization, Yadollah Shirmardi, as saying on Wednesday.

The official added that the safety pin of the grenade had been removed and that a piece of tape had been put in its place. Shirmardi suspected that the culprit wanted the grenade to explode ahead of the evening prayers when the area is usually crowded.

According to the official, the culprit sought to invoke fear in the minds of the Iranians who participated in the June 12 presidential election.

Officials in Tehran have called on all Iranians to remain vigilant.

The Tajrish shopping district is a popular tourist spot in the northern edge of Tehran. With its numerous bus stops, shopping malls and restaurants, Tajrish is one of the busiest areas in the capital.