A car bombing that targeted a bus carrying members of Iran's elite Revolutionary Guard in the country's far southeast has killed at least 27 soldiers and injured several dozen more, states news agencies reported Wednesday.

According to the Islamic Republic News Agency, the suicide attack against the Islamic Revolutionary Guard Corps took place on a highway near the city of Zahedan, located close to the borders of Pakistan and Afghanistan in Iran's Sistan and Baluchestan province, some 1,500 kilometers (932 miles) southeast of the capital, Tehran.

"In this suicide attack, a car filled with explosives blew up beside a bus carrying a unit of the Guards’ ground forces, causing the martyrdom and wounding of a number of the protectors of our Islamic homeland’s border," read a statement released by the IRGC.

While no group has claimed responsibility so far, the IRGC accused "Sunni terrorists" and "mercenaries of American intelligence services" of being behind the attack.

However, several Iranian media outlets have reported that the local terror cell Jaish ul-Adl ("Army of Justice") – a small offshoot of the Salafi militant group Jundallah ("Soldiers of God") – has claimed responsibility.

A few hours after the attack, the Iranian foreign ministry released a statement in which it vowed to avenge the deaths of the IRGC members and accused "countries in the region" of being responsible for the bombing.

"The self-sacrificing military and intelligence children of the people of Iran will take revenge for the blood of the martyrs of this incident," said Bahram Qassemi, a spokesman for the ministry, according to the semi-official Fars news agency.

The region of Sistan and Baluchestan is predominantly populated by the Baloch ethnic group, who are also present in the adjacent regions of Pakistan.

The occasionally restive area is a well-known route for opium trafficking and has been the location of a low-intensity insurgency carried out by Baloch separatists.

A previous attack by gunmen disguised as soldiers against a military parade in the western city of Ahvaz last Sept. killed at least 29 people, including 12 members of the IRGC.

That attack was claimed by the Islamic State terror organization.