Two British contractors helping the United Nations (search) organize landmark elections in Afghanistan and their Afghan interpreter were killed Wednesday in a remote eastern province Wednesday, officials said.

The two British men were killed in Nuristan province (search), about 100 miles east of the capital, Kabul, said Global Risk Strategies (search), a British-based security company.

"Both of the individuals involved were British nationals, working alongside the United Nations," the company said in a statement. It didn't release their names.

An Afghan interpreter also was killed in the attack, said U.N. spokesman Manoel de Almeida e Silva. The deaths were the first among Afghan and foreign staff preparing the country's first post-Taliban election, slated for September.

The company blamed the attack on "local bandits," but details were unclear. The U.S. military has warned repeatedly that Taliban-led militants were trying to derail the election process.

Farooq Wardak, the Afghan government's top election official, said the deaths would have "very serious consequences" — including deterring international monitors.

"The election wouldn't have that much international credibility" in their absence, Wardak said.

U.N. spokesman Almeida e Silva said there would be "at least a delay" in voter registration in Nuristan, but he vowed that the process would proceed uninterrupted elsewhere.

"It happened in a specific place," he said. "We look at security on a case-by-case basis."

Global Risk has been surveying parts of rural Afghanistan to help the United Nations decide where to open registration sites.

The United Nations is pressing ahead with its plans to register 10 million Afghan voters across the country despite a surge in violence in recent weeks.

The world body has registered almost 2 million Afghans in eight major cities, but only started signing up voters in the lawless countryside on Saturday.

U.S.-backed President Hamid Karzai (search) and the U.S. military insist that logistics, not security, is the main challenge to the elections. But the United Nations has warned that the vote will fail if security is not improved.

"This confirms what we've been talking about, that security is a major element in this process," Almeida e Silva said.

Slow registration already has forced Karzai, the favorite to win the election, to postpone the vote from June to September.

Nuristan is one of four troubled provinces along the Pakistani border where registrations were delayed because of poor security, Wardak acknowledged last week.

On Wednesday, Wardak said he hoped that registration could still begin as planned in Nuristan on Thursday, probably without any U.N. international staff.

Still, no date has been set for the process to begin in Zabul, Uruzgan and Paktika — other areas viewed as too dangerous for election work.

Last month, a roadside bomb was detonated by remote control in southern Kandahar as U.N. workers passed, forcing a suspension of all U.N. work in the region.

In March, U.N. officials were attacked with rocket-propelled grenades and gunfire as they slept in a government compound in southeastern Paktia province.