An explosion at an Iranian military training base has killed and injured several soldiers, the website of Iran's English-language Press TV reported.
The report did not make clear how many people were killed or injured but said the explosion on Tuesday was caused "by accident".
The explosion happened at a base in Khoramabad, the capital of Lorestan province in western Iran, according to Iranian media. Press TV said firefighters and rescue teams were sent to the scene and the injured were rushed to hospital.
The incident happened roughly three weeks after another deadly blast hit a military parade in northwestern Iran.
The blast at the parade, which killed 12 people and injured 80, occurred in the city of Mahabad. Iranian authorities blamed it on "anti-revolutionary" fighters backed by foreign enemies.
Days after that attack, Iran's elite Revolutionary Guards said they had killed about 30 people who were behind it.
Analysts have said attacks could raise pressure on Mahmoud Ahmadinejad, the Iranian president, whose government has been plagued by political infighting and economic woes linked in part to foreign sanctions imposed due to Iran's disputed nuclear programme.
No group claimed responsibility for the blast in Mahabad, which occurred during an annual ceremony for the Iranian armed forces to commemorate Iran's eight-year war with Iraq in the 1980s.
Last week, five Iranians, including four members of the security forces, were killed and nine injured when gunmen opened fire on a police patrol in the capital of Iran's Kurdistan province, the scene of frequent clashes between Kurdish guerrillas and Iranian forces.