The death toll from protests in Iran has reached 2,571 people, the US-based HRANA rights group said on Wednesday, as the Islamic Republic's clerical rulers face the biggest wave of dissent in years.

US President Donald Trump urged Iranians on Tuesday to keep protesting, promising help is on the way. Iranian officials, however, have accused US and Israel of fuelling violence in the country and blamed the deaths on "terrorist operatives" receiving foreign guidance to instigate.

The group said it had so far verified the deaths of 2,403 protesters, 147 government-affiliated individuals, 12 people aged under 18 and nine non-protester civilians.

An Iranian official said on Tuesday about 2,000 people had been killed, the first time authorities have given an overall death toll from more than two weeks of nationwide unrest.

Asked what he meant by "help is on its way", Trump told reporters they would have to figure that out. Trump has said military action is among the options he is weighing to punish Iran over the crackdown.

The unrest, sparked by dire economic conditions, has posed the biggest internal challenge to Iran's rulers for at least three years and has come at a time of intensifying international pressure after Israeli and US strikes last year.

Starlink offers free service in Iran

The satellite internet provider Starlink now offers free service in Iran, activists said on Wednesday.

Mehdi Yahyanejad, a Los Angeles-based activist who has helped get the units into Iran, told The Associated Press that the free service had started. Other activists also confirmed in messages online that the service was free.

“We can confirm that the free subscription for Starlink terminals is fully functional,” Yahyanejad said in a statement. “We tested it using a newly activated Starlink terminal inside Iran.”

Starlink has been the only way for Iranians to communicate with the outside world since authorities shut down the internet Thursday night as nationwide protests swelled and they began a bloody crackdown against demonstrators.

Starlink itself did not immediately acknowledge the decision.

Trump warns of ‘very strong action’

In an interview with CBS News on Tuesday, Trump vowed "very strong action" if Iran started hanging protesters, but again did not elaborate.

"I haven't heard about the hanging. If they hang them, you're going to see some things," Trump said.

According to the Norway-based Iran Human Rights Society, hangings are common in Iranian prisons.

Hengaw, an Iranian Kurdish rights group, has reported that a 26-year-old man, Erfan Soltani, arrested in connection with protests in the city of Karaj, will be executed on Wednesday. Authorities had told the family that the death sentence was final, Hengaw reported, citing a source close to the family.

Reuters could not independently confirm the report and state media has not reported any death sentences so far.

As he headed back to Washington from a visit to Detroit, Trump told reporters he would "look at the whole situation that's going on in Iran," adding: "Really bad stuff."

"The message (to the Iranian leadership) is they've got to show humanity ... It would seem to me that they have been badly misbehaving, but that is not confirmed."