Kampala, Uganda (CNN) -- Ugandan President Yoweri Museveni says sectarian and chauvinistic cultural leaders are behind weekend attacks by people, armed mainly with machetes and spears, who killed security personnel and civilians in the western part of the country.
Police raised the death toll to 90 on Tuesday afternoon. Hundreds have been arrested, police said, including cultural leaders of rival ethnic groups in the Rwenzori Mountains region and in the oil-rich Lake Albert region bordering the Democratic Republic of Congo.
Most of the dead "are attackers killed in a counterattack at a military camp in Bundibugyo district and civilians," police spokesman Fred Enanga said. "We have so far found 86 key suspects out of hundreds, and we continue with a cordon and search in the communities looking for 22 guns we lost.
"Most of guns were stolen at a police station and at a bank" where there are police guards and private guards, he added.
In a statement Tuesday, Museveni said the killings were the result of "schemes of some confused or a selfish bunch of people," adding that 51 attackers and eight security force members are among the dead.
"On account of chauvinistic ideas being bandied around for so long, it seems some groups hatched this criminal scheme that has caused the deaths of so many people," he wrote.
While the attacks were dealt with by the police and army, Museveni said, "of course, there was a failure of intelligence." He asks: "How did these people weave such a scheme without being preempted?"
Museveni says altogether, there were 13 daylight attacks across three districts in the Rwenzori Mountains and Lake Albert regions.