Blast reported in southern Iran
(CNN) -- A "geophysical exploration" caused a large blast Wednesday near the southern port city of Dailam in Iran, a local official in the Bushehr province said.
Oil exploration frequently takes place in the area, Iranian officials said. A reconnaissance team is en route to investigate, the official said.
There are no reports of casualties.
Initial reports from a Iranian state television included witnesses saying an airplane missile strike caused the blast. Later reports suggested a fuel tank falling from an airplane sparked the explosion. Officials said there is heavy air traffic in the area.
Russia has been building a nuclear plant in the city of Bushehr, about 90 miles southeast of Dailam.
Officials at the Russian Embassy in Tehran and at the Russian Ministry of Atomic Energy in Moscow -- which is overseeing the construction at the Bushehr nuclear plant -- told CNN in a phone interview there had been no explosion at the plant.
Ali Agha Mohammadi, the head of the security commission in Iran's National Security Council, earlier stated that a missile attack did not cause the explosion.