"Speaking about the Nabucco pipeline without Iran's participation would amount to nothing but a pipeline void of gas," Mottaki told FNA after an Iran-UAE joint economic commission meeting here in Tehran on Tuesday.
Earlier, US Special Envoy for Eurasian Energy Richard Morningstar had said that Iran is not in a geopolitical position to take part in energy projects in the southern European corridor.
"We have been constantly saying that, in our opinion, Iran is not in a position to become a part of any new projects in the Southern Corridor," Richard Morningstar said.
In reply, Iranian foreign minister told FNA, "We have never heard that Europeans have entrusted the Americans with their authority to decide on the pipeline."
The Nabucco gas pipeline project worth €7.9 billion envisages gas supply from the Caspian region to EU countries. Construction of the gas pipeline was scheduled for 2011. The first supplies will be launched in 2014. Maximal capacity of pipeline will hit 31 billion cubic meters per year.
The proposed 3,300-kilometer Nabucco pipeline aims to carry natural gas from Central Asia via Turkey and the Balkan states to Austria, bypassing Russia and Ukraine.
Participants of the project are Austrian OMV, Hungarian MOL, Bulgarian Bulgargaz, Romanian Transgaz, Turkish Botas and German RWE companies.
Iranian Oil Minister Gholam Hossein Nozari told FNA last week that Iran's participation in the project would be a must for the materialization of the project because the member states of the project will not be able to produce and supply the gas needed for the project.
Earlier in July, Managing Director of the National Iranian Gas Export Company (NIGEC) Seyed Reza Kassaeizadeh underlined that the Nabucco pipeline project would make no progress without Iran.
"It is obvious that Europe needs several gas supplying pipelines…Iran is the main gas supplier in the region and has rich resources, high security and proper infrastructure. In other words, Nabucco pipeline would not be materialized and would remain at the level a plan without Iran," Kassaeizadeh told FNA.
Russian Prime Minister Vladimir Putin said in March that the Nabucco project was not feasible without Iran's involvement.
Iran sits on 16 percent of the world's natural gas reserves - second in the world only to Russia.