Iran's Ambassador to the International Atomic Energy Agency (IAEA) Reza Najafi waits for the start of a board of governors meeting at the IAEA headquarters in Vienna, Austria June 4, 2018. (Reuters photo)

TEHRAN, June 6 (Xinhua) -- Iran will relaunch its nuclear activities if the Iranian 2015 nuclear deal fails, Iran's ambassador to the International Atomic Energy Agency (IAEA) said on Wednesday.

Iran has sent a letter to the IAEA on the start of certain nuclear activities, said the Iranian envoy Reza Najafi, according to Press TV.

"These are the preparatory work for a possible scenario if in an unfortunate situation the JCPOA (nuclear deal) fails, then Iran can restart its activities without any limits that already (exist) under the JCPOA," he said in the Austrian capital Vienna.

The first preparation is the restart of the Uranium Conversion Facility (UCF) in Iran's central province of Isfahan for the production of UF6, while another preparatory work concerns the infrastructure for the possible production of new centrifuges, Najafi said.

The Iranian official stressed that Iran's measure does not violate the JCPOA.

Iran's atomic chief said Tuesday that the Islamic republic is preparing the infrastructure for building advanced centrifuges.

Iran is holding talks with European countries on preserving the 2015 Iranian nuclear deal, officially known as the Joint Comprehensive Plan of Action (JCPOA), after the U.S. pullout of the deal in May.

Tehran has threatened in case other parties of the nuclear deal could not safeguard Iran's interests under the accord, Iran will quit and resume its nuclear activities even at full speed.