"Those exporting terrorism and the culture of violence are so notorious that no one will be duped into [believing] such accusations," said Iran's Foreign Ministry Spokeswoman Marzieh Afkham on Thursday.

In a statement the same day, the Bahraini Interior Ministry announced that authorities had arrested five people in connection with the July bombing in Sitra.

The statement carried by state news agency BNA also accused the Islamic Republic of involvement in the bombing. Manama had already made similar allegations against Iran following the attack.

Afkham said that Bahrain “ineptly” seeks to move against the constructive and diplomatic trend created following the widely welcomed agreement between Iran and six world powers on Tehran’s nuclear program, and advised the Manama government to tap into the potential created by regional relations to settle its domestic crisis.

The July 28 bombing in Sitra, which lies south of the capital, Manama, targeted a bus carrying policemen. The attack killed two police and wounded six others.

Following the blast, Iranian officials strongly condemned the attack and underlined the necessity to fight terrorism and extremism in the region.

Iranian authorities also dismissed as “unfounded” Bahraini state media propaganda which claimed that the explosives used in the attack were similar to those seized by security forces after allegedly being smuggled from the Islamic Republic.

The latest arrests in the tiny Persian Gulf monarchy come amid Manama’s heavy-handed crackdown on peaceful demonstrations for more than four years, which has left scores of people dead and hundreds of others injured.

The anti-government protesters call for the ruling Al Khalifa family to relinquish power.