The protests that have shaken Iran for nearly two weeks have continued across the country, including in the capital, Tehran, even as the government expands its crackdown to detain not just protesters on the streets but also public figures who have expressed solidarity with them.

In Zahedan, a city in the southeast with an ethnic Baluch population, tensions erupted on Friday (local time) with security forces firing at a crowd, and protesters attacking a police station with rocks and setting fire to a supermarket, according to videos posted on social media. Baluch activists claimed that security forces fired from a helicopter at a crowd gathered at the Maki mosque.

Dozens were killed and injured in the unrest. Nineteen were killed and 20 injured, including security forces, in Zahedan, the provincial governor said late on Friday. The news site Haalvsh, focused on news from Baluch areas, put the numbers at 36 dead and 50 injured. Iran’s state media called the unrest at the police station in Zahedan a “terrorist attack” that had forced security forces to fire back.

On Thursday night, crowds marched in the northwestern city of Sanandaj, in Kurdistan province, and in Mashhad, a city in the northeast, raising their fists and chanting, “Death to the dictator”. Elsewhere, women marched without hijabs in the southwestern city of Ahvaz, and protesters clashed with authorities in Qom, south of Tehran, and fled bullets fired by security forces in the southeastern city of Kerman, according to videos posted on social media.

Among those who have been arrested in the recent days are a soccer star, Hossein Mahini; and a performer, Shervin Hajipour, whose song about the difficulties of life in Iran has spread rapidly online.

Iran’s intelligence ministry said in a statement on Friday that nine foreign nationals – from Germany, Poland, Italy, France, Sweden and the Netherlands – were among those arrested. It said it had discovered nearly 80 pounds of explosives, which it tied to a terrorist group plotting to target public places.

Trying to deflate the protests, Iran has severely restricted and slowed down internet access, hindering the ability of Iranians to communicate with one another and with the outside world. Videos posted on social media arrive with hours of delay at the end of each day, meaning that there is limited information about whether protests are as widespread, in number and in geography, as they were in the earlier days of the unrest.

In Tehran, several residents said in telephone interviews that protests had scattered to the edges of the capital in smaller pockets. The city still had a tense atmosphere, and security forces were patrolling the streets, but normal life had resumed in most neighbourhoods, they said. Shops and offices in Tehran remained open, and children attended school.