Last month, a bomb blast went off at Komamboga near Kampala, leaving one person dead and several others injured.
A fresh investigation by the anti-terror squad then commenced as they trailed new groups that were threatening attacks on Uganda and neighbouring countries.
Police said the three suspected bombers at Komamboga disguised themselves as customers before planting the explosives under a table at the hangout. The Islamic State group (IS) later said it was behind the attack.
The explosion came one week after the UK government issued an alert of an imminent terror attack in Uganda.
It warned British citizens in the East African country – where attacks of this kind are rare – that “terrorists are very likely to try to carry out attacks”. It advised them to keep out of public places, including restaurants and bars.
Police spokesman Fred Enanga said the bombers ordered food and drinks at the bar, before placing a plastic bag under a table. The explosion went off moments after they left.
Investigators have found nails, ball bearings and other metal fragments, Mr Enanga added.
He said these indicated the blasts were caused by an improvised explosive device.
President Museveni said on Twitter that the blast was a terrorist act and promised to catch the perpetrators.
“The public should not fear, we shall defeat this criminality like we have defeated all the other criminality committed by the pigs who don’t respect life,” he said.
In the same month, at least one person died and several got wounded in an explosion on a bus en route to Mbarara, two days after a deadly attack in the Ugandan capital claimed by ISIL (ISIS).
