Amid the violence that engulfed several residential areas of the Kenyan capital following the declaration of controversial results of the presidential elections, women in particular have been targetted, with at least one hospital reporting a rise in the number of rape victims seeking treatment.

The Nairobi Women's Hospital said it had on 31 December received 19 rape cases, almost double the daily average.

Violence erupted mostly in the slums of Nairobi and other areas soon after the Electoral Commission of Kenya announced that incumbent President Mwai Kibaki had won the poll, beating his opposition rival challenger Raila Odinga, who immediately rejected the result citing alleged rigging of the poll in Kibaki's favour.

"It looked like it was mainly systematic gang rapes," said Sam Thenya, the chief executive officer of the hospital.

"This is just the tip of the iceberg," he said, adding that those who made it to the hospital had spoken of other rape survivors who could not seek treatment because the security situation prevented them from venturing out of the informal settlements or they lacked transport.

The rape victims in Nairobi came mainly from the slums of Kibera, Korogocho, Mathare and Dandora, according to Thenya. Violence has pitted mainly Odinga's supporters against communities perceived to have voted for Kibaki, with cases of reprisal attacks also being reported.

Sexual violence has also been reported against men, with the Kenyatta National Hospital in Nairobi on 2 January saying several men had been admitted after they were assaulted during the violence.

"There are several men admitted in various wards after they were subjected to forced circumcision," a source at the hospital said.

Odinga's core supporters come from the Luo ethnic group that does not practise circumcision, while Kibaki draws most of his following from the Kikuyu group, one of several tribes in which male circumcision is an essential rite of passage from adolescence to manhood.