Mystery Blast in Southern Iran

From The Guardian

TEHRAN, Iran (AP) - Iranian state television reported Wednesday that an explosion near the southwestern town of Deylam, about 110 miles from a nuclear facility, may have been caused by a fuel tank dropping from an Iranian plane. A government spokesman said the blast may have been caused by friendly fire.

However, Israel's Debkafile contradicts The Guardian:

Mystery deepens over big explosion above S. Iranian town of Deylam north of Bushehr Wednesday. Iran’s Revolutionary Guards now deny any attack or even a falling aircraft fuel tank.

Undeniable blast caused oil prices to shoot up by more than dollar past $48 per barrel and interrupted Iranian TV broadcasts. Nuclear installation is due to start operating in Deylam this year.

Rediff.com quotes CNN as reporting:

"A powerful explosion was heard this morning on the outskirts of Dailam in the Bushehr province. Witnesses said that the missile was fired from an unknown plane 20 kilometers (12 miles) from the city," CNN quoted Iran's Arabic language Al-Alam as saying.

But CNN's website does not mention the missile.

Update: Fox reports that Iran is now attributing the blast to an "industrial accident".