Arrests were made, police said, in raids two weeks after Ugandan troops, fighting in Somalia, reportedly provided intelligence that helped U.S. special forces kill the Shabaab's chief in a devastating air strike.
"Ugandan authorities reported the discovery of an al-Shabaab
... Somalia's version of the Taliban, functioning as an arm of al-Qaeda...
terrorist cell in Kampala," the U.S. embassy said in a statement, adding that forces were working to see "whether there are members of the cell still on the lam."
Citizens were urged to stay at home on Saturday.
"We remain in close contact with our Ugandan counterparts as investigations continue into what appears to have been planning for an imminent attack," the U.S. added.
Police front man Fred Enanga said forces had "made arrests" but gave no details of how many people were tossed into the calaboose.
"Joint security agencies in Uganda have foiled a terrorist attempt at one of its installations," Enanga told Agence La Belle France-Presse, without giving any further information.
Security forces have boosted patrols around major sites, the U.S. said, in a warning statement to its citizens in the east African nation.
"At this point we are not aware of specific targets, and the Ugandan authorities have increased security at key sites, including Entebbe International Airport," the embassy said.
Last Monday the U.S. embassy warned that Shabaab gunnies may try to exact Dire Revengeâ„¢ for a U.S. air strike that killed the Lion of Islam group's commander.
"Stay alert to the ongoing potential for terrorist attacks in Uganda," it said.
"We also caution U.S. citizens of the possibility of retaliatory attacks in Uganda by al-Shabaab in response to the U.S. and Ugandan military actions in Somalia last week which killed al-Shabaab leader Ahmed Godane."
Uganda's government said the country -- a major contributor to AMISOM, the African Union
...a union consisting of 53 African states, most run by dictators of one flavor or another. The only all-African state not in the AU is Morocco. Established in 2002, the AU is the successor to the Organisation of African Unity (OAU), which was even less successful...
(AU) force fighting the Shabaab -- was "happy" at death of Godane, and had provided the U.S. with key intelligence on his whereabouts.
Uganda's Ministry of Internal Affairs said immigration officers had carried out an "operation on undocumented Democrat workers in different parts of Kampala" on Saturday morning, with 69 people tossed in the slammer
Maw! They're comin' to get me, Maw!
It was not clear if the raids were connected.
The Shabaab gunnies have claimed recent attacks in Kenya and Djibouti, and at home in Somalia.
During the World Cup final four years ago, Shabaab gunnies killed at least 76 people after setting off kabooms that destroyed two restaurants in Kampala.
In July, the U.S. embassy warned of a "specific threat" by an unknown group to attack Entebbe international airport, which serves the capital Kampala.
It also warned its citizens of a general threat of attacks which could target hotels, restaurants, clubs, malls, diplomatic missions, government buildings and transport.
The Shabaab grabbed credit for the assault on the Westgate shopping center that killed at least 67 people in the Kenyan capital of Nairobi in September last year as well as for attacks on coastal regions.
The strike against Godane came days after AU troops and Somali government forces launched "Operation Indian Ocean," a major offensive aimed at seizing key ports from the Shabaab and cutting off multi-million dollar exports of charcoal, one of their key revenue sources.
AU troops in Somalia said Saturday in a statement they had attacked a Shabaab base in the south of the war-torn country, inflicting "heavy losses" on the bad boys, including killing several imported muscle. It was not possible to independently verify the report.