"Four low-orbit satellites weighing under 100 kilograms are under design and construction," Mohammad Soleymani was quoted as saying by the state broadcaster's website.
The other three will be high orbit spacecraft and all seven are being built by Iranian scientists, he said.
On February 2, Iran sent its first home-built Omid (Hope) satellite into space, carried by a Safir-2 rocket, setting alarm bells ringing among Western powers already at loggerheads with Tehran over its nuclear programme.
Hardline President Mahmoud Ahmadinejad said the launch of the satellite signalled Tehran's technological achievement and was an attempt to break the Western world's monopoly on science.
The West reacted strongly to the satellite launch, saying the technology could be diverted into developing long-range ballistic missiles capable of carrying nuclear warheads.
Iran denies seeking atomic weapons, insisting its nuclear and space programmes have peaceful aims.
A top Pentagon official said the satellite launch was "rudimentary" but warned that Iran was on a path to having a long-range missile.
