The bombing in downtown Tunis on Tuesday killed at least 11 people and injured 14.
Interior Ministry spokesman Walid Wkini confirmed that 11 security guards working for the presidency were killed.
The attack came 10 days after Tunisian authorities deployed more security forces and increased the security level in the capital.
Tunisia has been plagued by Islamist violence after the ouster of former President Ben Ali in 2011 uprisings.
Early this year, the IS carried out two attacks targeting foreigners, hitting hard the country's tourism industry.(IANS)