He said the increasing intensity of attacks in the south, southeast, and east of Afghanistan could disenfranchise parts of the dominant ethnic Pashtun population there.
"It is too soon to rule out attempts at causing major disruptions of the elections before, during or after polling day," Arnault said. "In addition, increased insecurity in the provinces along the eastern border is in itself a cause for concern for the elections in these areas."
The UN and Afghan Independent Human Rights Commission released a report on 22 August saying extremist attacks have increased against candidates, election workers, community leaders, and military forces this summer.
A Taliban spokesman said this week that the insurgents would not attack polling stations on election day on 18 September. But he vowed Taliban fighters would try to disrupt preparations for the polls.
Arnault said about 30,000 Afghan national police would be required to secure the "first ring" around about 6,300 polling centers. International military forces from Spain, the Netherlands, Romania, and the United States would provide back-up support, he said.
Arnault also said that almost $30 million was still needed from international donors for electoral costs, including ballot printing and transportation.
Pakistan's UN ambassador, Munir Akram, told the council his country was committed to securing its borders to block infiltrations into Afghanistan. He expressed disappointment those efforts have not been acknowledged by the UN.
"Seven hundred posts have been established along the border," Akram said. "Four thousand troops are being added for interdiction duties in the run-up of the Afghan parliamentary elections. Our troop strength on the border, I may mention, Mr. President, is higher than the combined strength of the national and international military presence within Afghanistan."
Pakistan is seen as the base for large numbers of rebels who cross into Afghanistan to launch attacks, before going back across the frontier. Vigorous efforts by Pakistani forces last autumn helped reduce activities by militants during the Afghan presidential elections.
Speakers at yesterday's Security Council meeting in New York stressed the importance of Afghanistan's 18 September polls proceeding peacefully. But many also said the country needs to focus on a postelection strategy for development, including more effective plans to eradicate the country's huge opium economy.
Iranian UN Ambassador Javad Zarif said his country, which has long battled drug traffickers from Afghanistan, had become alarmed at the increase in opium production.
"While certain efforts by the government of Afghanistan have resulted in the reduction of opium cultivation in some regions traditionally famous for opium producing, it is beyond comprehension why at the same time opium production should increase in areas bordering my country, especially in the Farah Province. It is a development that arouses our grave concern," he added.
Zarif also expressed disappointment at Afghan government delays in repatriating the millions of Afghans who have taken refuge in Iran in the past two decades.
Afghanistan: Violence Spiraling As Elections Near
Afghan Election Campaign Begins On Airwaves
For RFE/RL's full coverage of the Afghan elections, see "Afghanistan Votes 2004-05"