(CNN) A Toyota van loaded with explosives tried to ram the police headquarters in Iran's southeastern port city of Chabahar, killing two police officers and the attacker, Iran's state-run IRNA agency reported Thursday.

The suicide bomber blew himself up at around 9:55 local time on Thursday. Three of the 28 people injured in the attack are in grave condition, according to Mohammad Naseh, a chief medic at an emergency center in the city quoted by IRNA.

State media also reported shooting in the vicinity of the attack.

The Chabahar attack is the first suspected terror attack in Iran since gunmen attacked a military parade in the southwestern city of Ahvaz in September, killing at least 29 people and wounding more than 70 others.

Developing story -- more to come.