Iranian security forces have detained 10 people suspected of links to a suicide car bomb attack that killed at least two policemen earlier this week, police chief Hossein Ashtari said.
"Good clues have been obtained and hopefully with the public's cooperation ... we will get to the main leads," Ashtari was quoted by the state news agency IRNA as saying on Sunday.
More suspects have been identified and are being sought, Ashtari added.
At least 48 people were also wounded in Thursday's attack by a armed group on the police headquarters in the port city of Chabahar in southeast Iran.
While suicide bombings are rare in Iran, armed groups have carried out several attacks on security forces in recent years in Sistan-Baluchestan province, where Chabahar is located.
The province is home to a Sunni minority in the largely Shia country and has also long been plagued by violence from both drug smugglers and separatists.
The US-based SITE Intelligence Group and Iranian state media reported that Sunni armed group Ansar al-Furqan claimed responsibility for the attack.
Security in border areas
Iran has stepped up security in border areas after gunmen in September opened fire on a military parade in Iran's southwestern city of Ahvaz, killing 25 people, almost half members of Iran's elite Islamic Revolutionary Guard Corps.
The southeastern port city in Iran's Sistan-Baluchestan province is located near the border with Pakistan. The city hosts the operation of a joint port project between Iran and India by the Gulf of Oman.
Chabahar Port, which is being developed with funding from India, has been described as India's "golden gateway" that will help boost trade links to land-locked Afghanistan and Central Asia, while bypassing its regional rival, Pakistan.
In December 2010, at least 41 people were killed and 90 others wounded following a suicide attack near a mosque in Chabahar.
Another coordinated assault by fighters from the Islamic State of Iraq and the Levant (ISIL) group on June 7, 2017, targeted the parliament in Tehran and the shrine of Ayatollah Ruhollah Khomeini, the leader of Iran's 1979 Islamic Revolution, killing at least 18 people and wounding more than 50.
