At least 12 people in Iran have been killed amid anti-government protests, the country's state TV said Monday.
The demonstrations are the most serious political unrest in Iran since 2009 when millions took to the streets to protest alleged electoral fraud.
"Some armed protesters tried to take over some police stations and military bases but faced serious resistance from security forces," state TV reported.
It was unclear whether the deaths, up from two over the weekend, were connected to the incidents at the police stations and military bases.
Online videos in recent days have shown protesters attacking police stations. Other videos have shown protesters peacefully demonstrating and welcoming police.
Iran's semi-official ILNA news agency quoted lawmaker Hedayatollah Khademi, a representative for the town of Izeh, as saying two of the deaths happened there Sunday night during a demonstration over the government's handling of the economy. Izeh is about 280 miles southwest of Iran's capital Tehran.
Two other demonstrators were confirmed killed in western Iran late Saturday.
Khademi said the cause of deaths in Izeh wasn't immediately known.
Iranian judiciary chief Ayatollah Sadegh Larijani urged authorities to strongly confront rioters, state TV reported.
“I demand all prosecutors across the country to get involved and approach should be strong,” he said.
Nationwide protests erupted Thursday in Iran's second-largest city of Mashhad over economic issues and have since expanded to several cities.
Hundreds of people have been arrested.
“I do not know whether yesterday's shooting was done by rally participants or the police and this issue is being investigated,” Khademi was quoted by ILNA as saying.
On Twitter, President Trump has sought to portray the unrest as the direct result of "Iranian citizens fed up with regime's corruption & its squandering of the nation's wealth to fund terrorism abroad."
Trump added on Monday that the country was “failing at every level despite the terrible deal made with them by the Obama Administration.”
“The great Iranian people have been repressed for many years,” he wrote. “They are hungry for food & for freedom. Along with human rights, the wealth of Iran is being looted. TIME FOR CHANGE!”
While there is frustration over Iran's support for the regime of Syrian President Bashar Assad, Palestinians and Lebanon's Hezbollah, high unemployment, rising fuel prices and poor economic prospects are of far greater concern.
President Hassan Rouhani appealed for calm Sunday, but also warned of a crackdown.
"The government will show no tolerance for those who damage public properties, violate public order and create unrest in the society," he said in remarks on state TV.
Iranian authorities placed restrictions on some social media platforms used heavily in Iran, including Instagram and Telegram, in an attempt to prevent would-be protesters from using them to call for and organize further demonstrations.
Intense protests erupted in Iran in 2009 over allegations of electoral chicanery and other irregularities. Demonstrators accused former Iranian president Mahmoud Ahmadinejad of stealing the election and blocking genuine democratic movements.