"This morning a bomb inside a car exploded near a police station in Chabahar. Three people were killed and some others were injured," Chabahar's governor Rahmdel Bameria told state TV.
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Islamic Revolutionary Guards Corps (IRGC) Ground Force Brigadier General Mohammad Pakpour told semiofficial Tasmin News Agency such a "blind terrorist attack" would achieve no results.
Ansar al-Furqan, a Sunni jihadi group, claimed credit for the attack.
Chabahar lies in Sistan-Baluchistan near the border with Pakistan. The province has a Sunni Muslim ethnic Baluchi minority that straddles the border with Pakistan, where Baluchi separatists and jihadis are active.
Iranian Foreign Minister Javad Zarif blamed "foreign-backed terrorists" for the attack.
"Iran will bring terrorists and their masters to justice," he wrote on Twitter.
Uptick in terror attacksTerror attacks in Shiite Iran are rare, but militants have stepped up action in recent months. In September, gunmen dressed as soldiers attacked a military parade in Ahvaz, killing and injuring dozens. Arab separatists and the "Islamic State" (IS) issued competing claims for the attack, which prompted Iran to launch ballistic missiles at IS targets in Syria.
Read more: Attack on Iranian military parade may harden domestic and regional policies
In June last year, IS militants attacked parliament and the shrine of Ayatollah Ruhollah Khomeini, the leader of the 1979 Islamic Revolution, killing at least 18 people and wounding more than 50.
Iranian forces also regularly clash with Kurdish separatists along the mountainous border with the autonomous Iraqi Kurdistan region.
Tehran often blames the United States, Saudi Arabia and Israel for backing groups to destabilize Iran, something its rivals deny.
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cw/ng (AFP, AP, Reuters)