Iran says 120 of its nationals are being deported from the US, as part of President Donald Trump's crackdown on immigration.

"These individuals will return to the country within the next one or two days," Iranian foreign ministry official Hossein Noushabadi told Iran's Tasnim state news agency.

He said most of those being flown to Iran, via Qatar, had entered the US illegally - mainly through Mexico.

There has been an increased number of Iranians entering the US in recent years, including many who fear persecution at home.

White House spokesperson Abigail Jackson told the BBC: "The Trump administration is committed to fulfilling President Trump's promise to carry out the largest mass deportation operation of illegal aliens in history, using all the tools at our disposal."

Noushabadi said some of those being deported held valid US residency permits, adding that US officials had sought their consent for their return.

He called on the US government "to respect the rights of Iranian migrants and their citizenship rights under international law".

The New York Times, citing two senior Iranian officials familiar with the matter, said the flight of deportees was expected to arrive in Iran later on Tuesday.

Iran has been working with the US on a deal to removethe Iranian nationals through its US Interests Section at the Pakistani embassy in Tehran.

It is a rare instance of cooperation between Iran and the US, who do not have formal diplomatic ties.

Noushabadi said as part of the deal some 400 Iranian nationals are expected to be deported from the US, with this flight considered the first phase.

The US has already reached bilateral deportation agreements with a number of countries.

Earlier this year, Panama and Costa Rica agreed to take in several hundred African and Asian migrants from the US.

President Trump has repeatedly pledged to cut the flow of immigration to the US and plans to deport a record number of people living in the country without legal status - including to countries with controversial human rights records.

He has promised to "launch the largest deportation programme of criminals in the history of America" - but it is not known whether the Iranian nationals being deported have criminal records.

Trump's moves have drawn strong criticisms from human rights groups in the US and abroad, who say migrants face the risk of being sent to countries where they could be harmed.

In Iran, the regime's human rights record has been strongly criticised by rights groups, with UN experts also warning on Monday that there has been a "dramatic escalation" in the use of the death penalty this year.

The Iranian government has previously defended its use of executions, saying it is limited to only "the most severe crimes" - though human rights groups dispute this.