Tehran, Mar 16 (IANS): An Iranian police spokesman has said that more than 110 suspects have been arrested in connection with the suspicious poisoning of students at some schools, semi-official Tasnim news agency reported.

Following the reports of the school poisoning cases during the past few weeks, Iranian police increased the number of its patrol forces to 4,000 near the country's schools, Saeed Montazerolmahdi said on Wednesday.

Montazerolmahdi added some of the poisoning cases were real, but the majority of them were reported as a result of fear and anxiety, Xinhua news agency reported.

Iran's Interior Ministry said in a statement published on its website on Saturday that more than 100 people in 11 provinces had been arrested on charges of involvement in the recent incidents of student poisoning.

The Ministry added that some of the suspects had "hostile motivations," noting that they sought to cause fear and anxiety among people and students.

More than 700 students from 30 schools across Iran have fallen victim to mysterious poisoning cases after the first case was reported in the Qom province on November 30. Most of the students were soon discharged from the hospital after receiving treatment, according to the official news agency IRNA.

On March 6, Iran's Supreme Leader Ali Khamenei urged law enforcement authorities to pursue perpetrators and vowed to hand down severe punishment to them.

An investigation has revealed that the spread of certain "stimulant substances" among students led to their poisoning symptoms over the past weeks, the Iranian Interior Ministry said in a statement on March 7.