Kampala - Uganda's top opposition leader Kizza Besigye said poll results Saturday handing President Yoweri Museveni a fifth term should be rejected, in a statement issued while under house arrest surrounded by dozens of police.
"The results of the presidential elections must be rejected," Besigye's statement read. "We have just witnessed what must be the most fraudulent electoral process in Uganda."
The veteran 71-year-old Museveni won 60 percent of the vote in the sometimes chaotic elections, far ahead of the 35 percent garnered by Besigye.
International observers have also raised the red flag, warning that Uganda's electoral commission lacked transparency and accusing the police of heavy-handed treatment of the opposition.
"Today I am under house arrest. My home is sealed off and I am not allowed to leave. Nobody is allowed to access my home," Besigye said.
Police had stormed Besigye's Forum for Democratic Change (FDC) headquarters on Friday to arrest him, saying they wanted to prevent him from unilaterally proclaiming his vote score.
Besigye appealed to the "international community" not to recognize the results.
Also read: Uganda's Museveni wins 61% of votes with 83% counted: results
"Please reject the temptation to ratify these sham elections," he said. "But should you ratify the results of these sham elections, at least, have the courage to admit that you do not care about democracy or human rights in Africa."
Although Museveni was re-elected as president, at least 19 of his ministers lost their parliamentary seats, among them defence minister Crispus Kiyonga - who is spearheading regional efforts to end the political crisis in Burundi - and attorney general Fred Ruhindi.
Museveni and Besigye, 59, were once close. They fought together in a bush war to overthrow Uganda's first post-independence leader Milton Obote. During that time, Besigye served as Museveni's personal physician.
This was Besignye's fourth attempt to unseat his former comrade-in-arms, his best performance so far being in 2006, when he polled 37 percent.
"To my fellow Ugandans... remain vigilant and steadfast. The struggle is long and hard but, in the end, we shall win if we continue in our patient and steadfast resolve," Besigye added.
"The regime cannot survive without our co-operation. Let us denounce this electoral theft by withdrawing our recognition of the regime and ceasing to co-operate with it."