Iran has formally filed a complaint to the United Nations (UN) against the United States over the violation of its airspace with an unmanned drone earlier this month, which Tehran shot down, Tasnim news agency reported.

"The complaint was filed to the UN Security Council over the aggression against our airspace by the American drone ... the complaint states that Tehran reserves the right to respond firmly if the U.S. repeats the violation," Tasnim quoted Deputy Foreign Minister Gholamhossein Dehghani as saying.

Tensions spiked between Tehran and Washington since the U.S. withdrawal from the Iran nuclear deal, also known as the Joint Comprehensive Plan of Action (JCPOA), in May 2018. 

On Friday, a joint commission meeting of the JCPOA, headed by Iranian Deputy Foreign Minister Abbas Araqchi and the European Union (EU) Deputy Foreign Policy Chief Helga Schmid, is gathering representatives from the deal's remaining signatories in Vienna to discuss implementing the accord. 

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Iran's Foreign Ministry spokesman Abbas Mousavi earlier said that the meeting is the "last chance" to save the accord after the U.S. exit.

"I believe this meeting could be the last opportunity for the remaining signatories of the JCPOA to convene and seek how they can implement their commitments toward Iran," Mousavi added. 

EU announced in January the establishment of a payment channel, known as the Instrument in Support of Trade Exchanges (INSTEX), to secure trade with Iran and skirt U.S. anti-Iran sanctions after Washington's withdrawal.

But Iran said the EU's step is not enough since it has not been implemented yet.

(With input from Reuters, Xinhua)