TEHRAN, Iran (AP) — Iran's semi-official ILNA news agency is reporting that the country's space organization is cancelling a project to explore sending humans into space.

Iran sent a monkey into space in January 2013 and it had announced a goal of sending a person by 2018. But Wednesday's report quotes Mohammad Homayoun Sadr, deputy head of the space organization, as saying the cost was judged to be prohibitive — an estimated $15 to $20 billion over 15 years.

Iran has long held the goal of developing a space program, generating unease among the United States and other countries concerned about Tehran's ballistic missile programs.