The Iranian government has announced that it will take US President Donald Trump to the International Court of Justice over its assassination of the Islamic Republic's second most powerful man, general Qassem Soleimani.

Iran said it will file a war crime lawsuit at the Hague after the Quds Force top military commander was killed in a US drone strike in Iraq's Baghdad airport on January 3.

While Washington does not recognize the international tribunal's jurisdiction, the case could become a slap in the US' face if judges find Iran's case justifiable, which they have actually done in past trials. 

Agnes Callamard, a French human rights expert and special rapporteur to the United Nations, said the assassination of Soleimani most likely violates international law. 

Washington could face a major backlash - and turn public anger back to the US - if Iran's case prospers, following a flurry of domestic outrage over the downing of Ukrainian airliner that killed all its 176 passengers last week.

Iran, after initially denying it intentionally shot down the plane with missiles, admitted after three days of denial that its military was responsible for the tragedy.

According to state media, Iranian judiciary spokesperson Gholamhossein Esmaili said the US had made a 'terrorist act' by killing its top military commander, Qassem Soleimani.

Esmaili said they are planning to file charges in the International Court of Justice. At the time of Soleimani's murder, Callamard said it would be difficult to imagine how the US action in eliminating Soleimani was justifiable under international laws.

Callamard said that the murder of Soleimani and other top Iranian military officials "most likely" goes against international and human rights laws.

Legal justifications for such killings are narrowly defined and it is difficult to imagine how any of these can be applicable to these killings, Callamard pointed out.

The international criminal court has in recent years deliberated in Tehran's favor by mandating the US to ensure that sanctions against Iran did not infringe on humanitarian aid.

Iranian Foreign Minister Mohammad Javad Zarif on Thursday said the drone attack on Soleimani was "unprovoked," while Washington maintains that the general posed an imminent threat to Americans and the world.

Iran launched a barrage of rockets at US bases in Iraq, in response to Soleimani's death, calling the actions an act of "self-defense." Moments following Iran's reprisal, the Ukrainian commercial plane blew up on the skies in what Tehran now admits was unintentional and human error.

It took the Iranian authorities around three days alleging that the passenger plane had suffered a technical malfunction and denied reports that the shoot down was a psychological warfare.