The 5.1-magniture quake jolted the Qalehtal district, some 600 kilometers (370 miles) southwest of the capital, Tehran, at around 8:50 a.m. (05:20 GMT).
State radio said the children were injured in a stampede when they rushed out of their classrooms in a local school in Qalehtal. It also said some buildings in the district were slightly damaged.
The report said the quake was felt in many cities and towns across the southwestern oil-rich province of Khuzestan. It said no deaths or damage were immediately reported.
Iran is located on seismic fault lines and is prone to earthquakes. It experiences at least one slight earthquake every day on average.
In March 2006, three earthquakes and nine aftershocks hit western Iran, in quick succession, killing at least 70 people and injuring about 1,200.
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