Iranian army troops conclude their march in a military parade marking the 35th anniversary of Iraq’s 1980 invasion of Iran, in front of the shrine of late revolutionary founder Ayatollah Khomeini, just outside Tehran, Iran, Tuesday, Sept. 22, 2015.

:: An Iranian soldier opened fire on his colleagues, killing four and wounding 8 of them at a military air base in south Tehran, according to local news outlets.

Previousely the semi-official Mehr news agency’s report offered no motive for the attack but it said that it took place in Kahrizak, which is on the southern outskirts of Tehran.

All injured soldiers were taken to an Air Force hospital in southeast of the city, the report said.

The reported shooting is the latest to strike Iran.

In July, a soldier opened fire on his comrades, killing three and wounding six at a military base in the town of Abyek, some 62 miles (100 kilometers) west of Tehran. The assailant reportedly shot himself in the incident, but survived and was taken to a nearby hospital.

In September, a soldier killed himself after shooting to death three of his comrades in the south of the country.

Military service of up to 24 months is mandatory for men age 19 and above in Iran.