Iran says it is ready to charge 48 individuals who authorities believe are “perpetrators and masterminds” behind the assassination of top general Qassem Suleimani a year ago in Iraq.
The comments came as Iran’s supreme leader Ayatollah Ali Khamenei said “revenge ... is certain and will be exacted at the right time”, state news agencies reported.
Iran has identified the leaders of the attack, where it was carried out from and who gave information about the operation to the US, said Hossein Amir Abdollahian, special aide to the Iranian parliament speaker for international affairs.
Suleimani, who headed the Islamic Revolutionary Guard Corps Quds Force that specialised in overseas military intelligence and asymmetric warfare, was killed in a US drone strike near Baghdad airport on January 3, 2020.
“All the documents needed for issuing the criminal indictment against the assassins are ready,” said Mr Amir Abdollahian, who is also the spokesman for the committee to commemorate the death of the general.
A year of tensions with Iran - in pictures
"Iran's Judiciary has been busy during the past year to collect the documents in and out of the country," he said. They were able to identify who passed information regarding Suleimani's travel from Beirut to Damascus and then on to Baghdad, where he was killed.
He said the indictment would "surely be a deterrent" against further such attacks.
In June, Iran said it would execute a man it accused of giving intelligence to the US and Israel that helped kill the top Iranian general.
Judiciary spokesman Gholamhossein Esmaili accused Mahmoud Majd of receiving “large sums” from Israel’s Mossad and the CIA to help plan the assassination.
Iran condemned US claims that the targeted killing fell under its fight against terrorism.
The attack also killed Abu Mahdi Al Muhandis, deputy commander of the Iran-backed Iraqi militias known as the Popular Mobilisation Forces (PMF), and eight others near Baghdad International Airport.
Iranian Foreign Minister Javad Zarif said Suleimani was on a diplomatic mission at the time, a claim that US Secretary of State Mike Pompeo and other US officials strongly denied.
The US is concerned that Iran will use the anniversary and the final days of the Trump administration to carry out a revenge attack for the killing of Suleimani.
On Wednesday, the US flew two strategic B-52 bombers over the Arabian Gulf for the second time in a month. The flyover was intended to be a show of force to deter Iran from attacking American or allied targets in the Middle East.
US intelligence detected recent signs of “fairly substantive threats” from Iran, and that included planning for possible rocket attacks against US interests in Iraq in connection with the anniversary, AP quoted a top US military source as saying.
The tensions come as Iran's Cabinet says it will pay out $150,000 in compensation to families of those killed when it shot down a Ukrainian airliner when it retaliated against the US by firing rockets at American troops in Iraq five days after the Suleimani killing.