Nigeria's intelligence agency said it has been warning shopping complexes in Abuja for two weeks that Islamic extremists might attack them in the capital, where a blast at a mall killed 22 people this week.
The increased security may have prevented even more carnage as witnesses said a security guard stopped a car bomber from entering the mall moments before the massive explosion on Wednesday.
Survivor Donald Chikason told ThisDay newspaper that a security guard argued with the driver of a car who wanted to enter Emab Plaza through the exit gate.
When the guard refused, the man bent down and moments later the car exploded, today's edition of the newspaper quoted him as saying.
"The man started arguing, behaving as if he was drunk," it quoted him as saying.
Chikason, who works at a bank in the mall, was knocked out by the blast and only regained consciousness in the hospital. The explosion was heard miles (kilometres) away. It set 17 vehicles ablaze and shattered windows throughout the four-story complex.
Body parts lay around the exit gate, other witnesses told The Associated Press. Dozens of wounded survivors were recovering in the hospitals today, most suffering burn wounds like Chikason, but at least one victim's leg was amputated, doctors said.
Nigerian intelligence received information that Boko Haram extremists were planning such an attack, said spokeswoman Marilyn Ogar of the Department of State Security.
"About two weeks ago we heard information that they were planning an attack at a busy shopping mall or market ... And so we had to go from one shopping complex to another trying to tell people to be more aware," she told The Associated Press.
Emab Plaza is the biggest and busiest in Abuja, the nation's capital in central Nigeria. The explosion occurred around rush hour as many residents were hurrying to view Nigeria's Super Eagles match against Argentina at the World Cup in Brazil.
The state security department did not publish the intelligence about the threat to shopping malls, apparently to avoid a panic.
President Goodluck Jonathan visited the scene of the latest blast and victims in the hospital today, after returning home hastily last night and cutting short his participation at an African Union summit in Equatorial Guinea.
Speaking to reporters at the main hospital, he sympathised with victims and their families and called the 5-year-old Islamic uprising "one of the darkest phases in the history of our nation." Still he said he was confident "we shall surely pass through this" and promised the perpetrators would be brought to book.
