Intimidation of candidates for the upcoming vote for the lower house of parliament in Afghanistan undermines reconciliation, Washington said.
Afghanistan is preparing for Sept. 18 elections for the Wolesi Jirga, the lower house of parliament.
Five men supporting Afghan provincial female candidate Fawzya Galani were found dead last weekend. Abdul Manan, a candidate from Herat province was killed on his way to an area mosque during the weekend as well.
The U.N. Assistance Mission in Afghanistan said it was unclear who carried out the attacks.
U.S. Secretary of State Hillary Clinton condemned the attacks in the strongest possible terms, saying it obstructed democratic reforms in the war-torn country.
"Violent intimidation of electoral candidates and their supporters undermines the right of all Afghans to a peaceful and democratic future for their country and those responsible for the killings must be brought to justice," she said in a statement.
Clinton said it was especially important for Afghan authorities to make sure women are able to take part in the elections.
There are more than 2,500 candidates scheduled to compete for the 249 seats in the Wolesi Jirga. The number of women competing for the estimated 64 seats reserved for women on the 249-seat parliament rose from 328 in 2005 to 406 for upcoming elections.
U.N. officials said they are concerned the security situation in Afghanistan could undermine the significance of the vote.
