* Bombers target fans in northeast Nigeria, Tanzania
* Kenyan, Ugandan, Nigerian police issue warnings
* Huge challenge to protect small, makeshift centres
By Elias Biryabarema and Andrew Heavens
KAMPALA/ABUJA, June 9 (Reuters) - Guards search customers and peer into bags at Kampala's Kyadondo bar, almost exactly four years after militants set off explosives in a sports ground outside, killing dozens of fans watching the last World Cup final on a giant screen.
The crowd is small and mood subdued - but Edmond Twebembere does not want to let security fears spoil his night out. "I love the place, maybe too much ... So, as scary as the history is, I decided I will come," said the 32-year-old. "I could still die somewhere else."
It is a attitude that has helped Kyadondo bounce back from the assault. But a spate of more recent attacks has highlighted the vulnerability of thousands of much less substantial venues were African crowds will gather to cheer on this year's contest.
Makeshift structures with televisions set up in back allies, public squares and open-sided shacks, the viewing centres scattered across towns and villages would stretch even the best-equipped security force trying to protect them.
"Attacks targeting screening venues have already started ahead of the World Cup ... and are likely to continue even after the final on 13 July," IHS Country Risk analyst Robert Besseling wrote in a report issued on Monday.
In East Africa, the main threat is al Shabaab, an al-Qaeda-linked group that is killing civilians to punish their governments for sending troops to confront its fighters in Somalia. Across the other side of the continent, in Nigeria, another threat comes from Islamist movement Boko Haram.
For both groups, viewing centres offer more than just another conveniently poorly guarded public meeting place.
The combination of soccer and often alcohol is, for them, the ultimate demonstration of corrupting Western influence. "There is a common credence amongst groups including Boko Haram that watching football matches is un-Islamic ... Anyone participating in events that don't align with their vision is potentially a target," said Control Risks analyst Roddy Barclay.
Memories of the Ugandan blasts echoed across the continent last week when suspected Islamist militants set off a car bomb that killed 18 people watching a game on television at a centre in Nigeria's northeastern Adamawa state.
A week before, a suicide bomber set out to strike an open-air screening of a match in Nigeria's central city of Jos. His car blew up on the way, killing three people.
A blast wounded 15 people watching an English Premiership soccer match at a pub in the Tanzanian city of Arusha in April.
Nigeria's army has issued a nationwide warning to tighten security at the centres. Uganda's police said there were new "strict regulations" on venues screening live matches.
Kenya - which is still reeling from the deadly September raid on its capital's Westgate shopping mall and a string of grenade and bomb attacks - stepped up police patrols around venues and told managers to "register and screen" fans.
"GOD PROTECT US"
Cafes and matches are also regularly hit in Somalia, where the spokesman for the capital's mayor said on Monday security forces and ambulances had been put on high alert.
Two Somali suicide bombers accidentally blew themselves up close to a stadium in Ethiopia's capital where fans watched a World Cup qualifying match against Nigeria in October last year.
Locals were more at risk then Westerners, who were more likely to have their own satellite connections or to attend venues with better security, analysts said.
Across Nigeria's northeast, many fans told Reuters they would take responsibility for their own security by going to friends' houses or just missing matches.
"Boko Haram appears to be targeting viewing centres, drinking joints, any social gathering. My wife has started warning me not to think of going to viewing centres this time," said Ahmed Yusuf, a long-time FC Barcelona fan in Borno state capital Maiduguri.
Staff at the Albash Viewing Center in the central city of Kaduna had installed a metal detector and started watching out for unfamiliar faces, said 33-year-old owner Bashir Idris.
"This is my only source of livelihood where I take care of those working under me, my wife and my seven children," he said. "So we will not take any chances at all and we are praying to God to protect us throughout the World Cup." (Additional reporting by Isaac Abrak in Abuja, Joel Duku in Damaturu, Garba Muhammad in Kaduna, Lanre Ola in Maiduguri, Abdi Sheikh in Mogadishu, Edmund Blair and Humphrey Malalo in Nairobi and Emmanuel Ande in Yola; Writing by Andrew Heavens; Editing by Tim Cocks, Larry King)