Iran has dismissed criticism by the UN's human rights chief on the killing of protesters during demonstrations over water shortages.
Meanwhile, rallies in support of the protests in Khuzestan province spread to the north-west of the country on Saturday, according to videos posted on social media.
UN High Commissioner for Human Rights Michelle Bachelet on Friday expressed concern about deaths, wounded protesters and widespread detentions over the past week in the oil-rich province in the country's south-west.
Iran's Foreign Ministry spokesman Saeed Khatibzadeh said in a statement carried by Iranian media that Ms Bachelet's "interventionist" and "non-expert and biased comments on the management of the country's water resources were not within the scope of commissioner's responsibilities".
In addition to the drought, Mr Khatibzadeh said US sanctions had "prevented the transfer of technology to and investment in Khuzestan's water sector".
Iranians have taken to the streets for more than a week to vent their anger about the shortages that have come during the country's worst drought in half a century and as the economy suffers under the weight of US sanctions and the Covid-19 pandemic.
Social media videos on Saturday showed groups of demonstrators in the north-western city of Tabriz chanting slogans in support of protesters in Khuzestan. Reuters could not verify the footage.
Late on Thursday, one youth was shot dead while seven were wounded during solidarity demonstrations in neighbouring Lorestan province, a police official said, blaming "counter-revolutionaries" for the violence.
Videos on social media on Friday showed people marching in the city of Aligudarz and chanting slogans against Iranian supreme leader Ali Khamenei.
At least one policeman and three young men were shot dead in earlier protests, according to Iranian officials who blamed "rioters" for the deaths.
However, Amnesty International said at least eight people had been killed during the unrest.
The Human Rights Activists News Agency said on Saturday that it had been able to identify 10 killed and 102 detained.
Witnesses spoke of continued heavy security presence in Khuzestan on Saturday.
"Mobile internet is still down and there are security forces everywhere," a resident of the provincial capital of Ahvaz, who asked not to be named, told Reuters.
Khamenei on Friday called on officials to deal with the crisis, saying people could not be blamed for protesting over water shortages.
Mirroring Khamenei's position, President Hassan Rouhani said on Saturday that "with the exception of a few, people are exercising their legal right to protest."