New Delhi: Iran on Saturday lashed out at Pakistan and warned the country that it would pay a heavy price for harbouring terrorists. It accused Islamabad of providing safe havens to suicide attackers, the state television of the country reported. Iran made this thundering attack days after 27 Revolutionary guards were killed in a suicide attack perpetrated by jihadists that Tehran accuses Pakistan of supporting.

Tens of thousands of Iranians called for "revenge" at the funeral of the 27 deceased soldiers.

Major General Mohammad Ali Jafari, referring to jihadist outfit Jaish al-Adl ("Army of Justice"), said that the country will pay a very heavy price for spreading terrorism. He said to the mourners, that the Islamic Republic of Iran will no longer observe the previous reservations and will directly act to counter such act.

Iran’s attack comes days before its regional arch-rival Saudi Arabia’s crown prince Mohammed-bin-Salman’s visit to Pakistan.

Jafari blamed Pakistan's army and Inter-Services Intelligence agency, saying that "sheltering and silence" amounts to supporting the perpetrators.

On Wednesday, a suicide bombing targeted a busload of Revolutionary Guards in the volatile southeastern province of Sistan-Baluchistan, which sits astride the border with Pakistan. The assault was allegedly perpetrated by Jaish al-Adl , which was formed in 2012 as a successor to the Sunni extremist group Jundallah, which waged a deadly insurgency for a decade before it was severely weakened by the capture and execution of its leader Abdolmalek Rigi in 2010.

On Thursday Pakistan backed terror outfit Jaish-e-Mohammed carried out a major attack at a CRPF convoy, in which 40 soldiers were martyred .