At least four police officers killed in attack in south-east Iran

Group shot dead on patrol in Zahedan near border with Afghanistan and Pakistan

Iranian soldiers participate in military manoeuvres in Sistan and Baluchestan province, 50km east of Zahedan. Fars News via AP

At least four police officers have been killed in south-east Iran in what state media called a "terror attack".

The patrol officers were shot dead inside their vehicle in Zahedan, the capital of the restive south-eastern province of Sistan and Baluchestan.

Tasnim News, the semi official news agency affiliated with the Islamic Revolutionary Guard Corps, said terrorists ambushed the patrol car and shot at officers.

The Sunni-majority province bordering Afghanistan and Pakistan is no stranger to unrest and security forces in the area often come under attack.

Authorities were on Sunday looking for the attackers, Tasnim said, but did not provide any further details on the suspects or a potential motive.

Two police officers were killed in an attack on a police station in the province earlier this month, while five border guards were killed in armed clashes in May.

The region has played host to clashes involving drug-smuggling gangs, rebels from the Baluch minority and Sunni extremist groups.

Violent battles have also been reported with the Afghan Taliban, who are at odds with Tehran over water disputes in border areas.

Zahedan is also known for anti-regime protests after nationwide rallies erupted last autumn following the death of Mahsa Amini who was arrested by morality police after wearing her hijab "inappropriately".

Dozens were killed in a single day – known as "Bloody Friday" – in a crackdown on Zahedan protesters on in November, when security forces opened fire following Friday prayers.

Sunni clerics in the city have also been threatened and arrested over their outspoken support of the protests.

Several people have been executed for joining the movement, accused of murdering members of the security forces in closed-door trials widely condemned as sham proceedings.

Up to 15 million Baluch people live in Iran, Afghanistan and Pakistan, of which around two million reside in Iran, mainly in Sistan and Baluchestan.

Like several other ethnic groups in Iran including the Kurds, many feel little connection to the theocratic government which took over the country in 1979.

Many Baluchis claim they are economically and politically marginalised in both Iran and Pakistan and there have been several Baluch insurgent movements in both countries since the late 1940s.