MOMBASA: The death toll in Kenya's restive coastal region rose to at least 17 on Monday in two attacks on police by machete-wielding men hours before voting began in a tense presidential election, police officers said.

The authorities suspect at least one of the attacks was carried out by members of a coastal separatist group who had threatened to disrupt voting if their demand for secession of the Indian Ocean coastal strip was not met.

Senior police officers said the death toll was comprised of nine security officers, two civilians and six attackers.

A remote-controlled bomb was also set off in the northeastern town of Mandera, a town on the restive border with war-torn Somalia, but resulted in no casualties.

“There have been no casualties and voting is still going on,” in Mandera, Kenyan police chief David Kimaiyo said about the blast.

Leading presidential candidate Prime Minister Raila Odinga said the violence was “very regrettable” and condemned in “the strongest terms possible this heinous act of aggression”.

Independent Electoral and Boundaries Commission (IEBC) chairman Ahmed Issack Hassan condemned the outbreaks of violence, including in the northeastern town of Garissa.

“In Mandera there was an explosion, in Garissa there was an incident of shooting and in Coast (region) there was an incident of violence,” Issak Hassan told a press conference. “Security has been beefed up in those regions.”The IEBC chief also acknowledged some logistical problems.

“Some few polling stations opened late. In some others the coordination of the queueing of voters was not well done,” he said.

However, European Union election observer mission chief Alojz Peterle said initial reports indicated that “most polling stations opened on time, high turnout with big queues, mostly patient and calm.”