The group said that some of its members detonated an explosive device in a bar where "members and spies of the Ugandan government were gathering" in Kampala, Reuters reported.
The bomb, packed with nails and shrapnel, targeted a restaurant on the outskirts of the capital, police said on Sunday.
The explosion killed a 20-year-old waitress and injured three people, two of whom were in critical condition, police said, adding that all indications suggest an act of domestic terror.
President Yoweri Museveni said the attack "seems to be a terrorist act".
ZZ/PR