TEHRANinfo-icon: Iraninfo-icon's supreme leader Ayatollah Sayed Ali Khamenei on Friday warned residents of the drought-hit southwest not to give ammunition to the "enemy" after days of protests that have seen at least four killed.

Khuzestan, Iran's main oilinfo-icon-producing region and the wealthiest of the country's 31 provinces, has been gripped by drought since March, with protests erupting in several towns and cities since July 15.

Addressing residents of Khuzestan, Ayatollah Khameneiinfo-icon said: "The people have expressed their discontent, but we can't criticise them for that. The water problem is not a minor one, particularly in Khuzestan's hot climate."

Ayatollah Khamenei stated that he had repeatedly notified officials before about the need to address the water issue in Khuzestan.

"If those recommendations had been taken into account, the current situation would certainly have not arisen. It is painful to see that the loyal people of Khuzestan, in spite of all their facilities, natural potentials and factories in the province, are dissatisfied and upset."  

Describing the problem as "one of the really painful worries" Ayatollah Khamenei however urged people to be cautious..

"The enemy will try to use any tool against the revolution, the nation and the people's interests, so we must be careful not to give him any pretext," Ayatollah said.

Iranian mediainfo-icon and officials have said at least three people have been killed, including a police officer and a protester, accusing "opportunists" and "rioters" of shooting at demonstrators and security forces.

State television said on Friday that a fourth person was killed the previous night and two wounded during "rioting" in the town of Aligudarz, in the western province of Lorestan.

It said people had taken to the streets "on the pretext of the water problems in Khuzestan".

"Shots were fired by unknown elements," the broadcaster said, adding that the security forces were deployed to tackle the situation.

It was the first time local media had reported protests or casualties outside Khuzestan since the water protests broke out last week.

Farsi-language media based abroad have broadcast videos they said were of protests in several towns and cities in Khuzestan, showing hundreds of people marching and chanting slogans against the authorities while surrounded by anti-riot police.

Authenticity of the videos could not be independently verified.

Global rights watchdogs Amnesty Internationalinfo-icon and Human Rightsinfo-icon Watch meanwhile alleged that Iranian security forces have used "unlawful and excessive force" to quell the protests in Khuzestan.

UN rights chief Michelle Bachelet on Friday told Iran to address the chronic water shortage in the province instead of cracking down on protesters.

"Shooting and arresting people will simply add to the anger and desperation," she said, adding that the "catastrophic" situation had been building up for many years.

The day before, President Hassan Rouhani said in a televised speech that residents of Khuzestan had "the right to speak, express themselves, protest and even take to the streets, within the framework of the regulations".

Admiral Ali Shamkhani, secretary-general of Iran's Supreme National Security Council, said the security forces had been ordered "to immediately release those detained during the recent incidents in Khuzestan who had not committed a criminal act".