In a statement yesterday, Guterres spokesperson said that "the Secretary-General strongly condemns the terrorist attacks."
At least 13 people were killed and about 46 injured in the attacks on the mausoleum of Ayatollah Ruhollah Khomeini and the Parliament (Majlis) building.
Guterres called for those responsible for "this unjustifiable violence" to be brought to justice.
"All countries must work together in fighting terrorism while upholding the universal rights and values that bind the global community," the spokesperson said.