Iran accuses US of 'dangerous act' in drone spying

Iran has accused the United States of "a very dangerous and provocative act" after a drone entered its airspace, justifying its decision to shoot the aircraft down.

Iran's ambassador to the United Nations, Majid Takht Ravanchi, made the claim in a letter to UN Secretary-General Antonio Guterres and the Security Council.

He said the US craft was engaged in a "clear spying operation" and called its flight a "blatant violation of international law," saying Iran reserved its right to "take all appropriate necessary measures against any hostile act violating its territory."

Ravanchi added that Iran was not interested in war with the US.

The US said that the spy drone was some 34 kilometres from the nearest point in Iran when it was shot down over the Strait of Hormuz by an Iranian surface-to-air missile.

The Pentagon released a graphic pinpointing the position of the drone on a map of the Strait of Hormuz, the strategic passage through which much of the world's oil passes.

The drone downing comes amid high tensions between the US and Iran, which was already accused by Washington of carrying out attacks on tanker ships.

Tehran denies being behind the attacks but has frequently threatened to block the sea lanes used to move much of the world's oil exports.

Tensions between Tehran and Washington have grown since the US last year unilaterally quit the 2015 nuclear deal and reimposed sweeping sanctions on Iran.