Iran acknowledged as a failure Wednesday its attempt to send a live monkey into space last month -- touted as its first step towards launching a man into space.

"The Kavoshgar-5 rocket carrying a capsule with a live animal (a monkey) was launched during Shahrivar," an Iranian calendar month spanning August 23 to September 22, Deputy Science Minister Mohammad Mehdinejad-Nouri was quoted as saying by the ISNA news agency.

"However, the launch was not publicised as all of its anticipated objectives were not accomplished," Mehdinejad-Nouri told reporters.

He said the launch of a live animal into space was "strategic, and a priority," and expressed hope that future launches would attain more of the objectives set.

On October 3, Iran indefinitely postponed plans to send a live monkey into space, without giving any reasons.

"One cannot give a set date for this project and as soon as our nation's scientists announce the readiness (of the project) it will be announced," said Hamid Fazeli, head of Iran's Space Organisation.

The project envisaged launching a capsule with life support using the Kavoshgar-5 rocket to an altitude of 120 kilometres (75 miles) for a 20-minute sub-orbital flight.

The project was unveiled in February by President Mahmoud Ahmadinejad.

At the time, Fazeli touted the launch of a large animal as the first step towards sending a man into space, which Tehran says is scheduled for 2020.

In mid-March, Iran announced the successful launch of an earlier version of the rocket, Kavoshgar-4, carrying a test capsule designed to house the monkey.

Iran has already sent small animals into space -- a rat, turtles and worms -- aboard a capsule carried by its Kavoshgar-3 rocket in 2010.

The Islamic republic, which first put a satellite into orbit in 2009, has outlined an ambitious space programme amid Western concerns the rocket technology may be linked to developing ballistic missiles that could deliver nuclear warheads.

Tehran has repeatedly denied that its nuclear and scientific programmes mask military ambitions.