TEHRAN: Fifteen Iranian servicemen were killed and several others seriously wounded in an explosion on Saturday at a military base near Tehran that happened as troops were moving ammunition, a Revolutionary Guards spokesman told state TV.

"My dear colleagues in the Revolutionary Guards were moving ammunition in one of the arsenals at that base when, due to an incident, an explosion happened," Ramezan Sharif told news channel IRINN.

"Some of the casualties are reported to be in a critical condition," he added.

The blast was so big it was felt in western suburbs of Tehran, 45 km away, witnesses told Reuters. Many assumed there had been a low-level earthquake. Some media reports said the initial blast was followed by a second explosion.

There were no reports linking the blast to any air strike or other attack. Tension has risen in recent weeks between Iran and its enemies Israel and the United States, which have not ruled out striking nuclear facilities they believe are working towards making atomic weapons, a charge Tehran denies.

On Oct. 12 last year a similar blast at a Revolutionary Guards munitions store killed and wounded several servicemen in Khoramabad, western Iran. Authorities said that explosion was an accident.