NAIROBI, Kenya (AP) — Four people have been killed in opposition demonstrations this month as Kenya's fresh presidential election approaches next week, national police said Friday, as concerns rose about violence around the vote.

The deaths occurred in "confrontations between rioters and police officers" between Oct. 2 and Monday, the statement said.

Earlier this week, Human Rights Watch and Amnesty International accused police of killing 67 people in opposition protests since August's election results were announced.

The Supreme Court nullified President Uhuru Kenyatta's victory, citing irregularities, and ordered a fresh election. Opposition leader Raila Odinga, whose legal challenge led to the ruling, has withdrawn from the new vote and said it risks having the same flaws.

Opposition protests demanding electoral reforms have continued, with witnesses saying police dispersed some with tear gas and gunfire.

It remained unclear just how the Oct. 26 will be carried out. This week, two members of Kenya's electoral commission cast doubt on whether the vote can be free and fair. One resigned and fled the country, saving she feared for her life.

The commission has said the vote will go ahead with all of the candidates who ran in August — and that Odinga had not turned in the official withdrawal form.

Kenyatta said Friday that security has been "enhanced and appropriately deployed" to keep the new vote free from violence.