Top Iran cleric links suicide blast to foreign spy services Iran's top cleric links suicide bombing that targeted Revolutionary Guard, killing at least 27, to foreign spy agencies

TEHRAN, Iran -- Iran's Supreme Leader Ayatollah Ali Khamenei has sent condolences to the families of the victims of a suicide car bombing that struck a bus carrying Iran's elite Revolutionary Guard troops, killing at least 27 people.

An al-Qaida-linked group, Jaish al-Adl, claimed responsibility for Wednesday's attack in Iran's restive southeastern Sistan and Baluchistan province. Tehran linked the bombing to an ongoing U.S.-led conference in Warsaw largely focused on Iran.

Khamenei's letter, published on his website, Khamenei.ir, claimed the perpetrators had links to spy organizations of countries in the region and beyond.

President Hasan Rouhani asserted that the U.S. and Zionism are at the root of "terrorism in the region" and urged neighboring countries to help "stop terrorist attacks."

Pakistan's foreign ministry spokesman Mohammad Faisal said Pakistanis were "shocked and grieved."