The Taliban has for the first time threatened to attack polling stations directly, stepping up warnings for Afghans to boycott landmark elections this week.
The threat was made in leaflets pinned up and dropped in villages in southern Afghanistan.
The leaflets say residents must not participate in the elections so as not to become a victim of Taliban operations.
They say the Taliban is using new tactics targeting election centres.
About 30,000 extra United States troops have been deployed in the country in the leadup to the poll, raising the total to 62,000.
Combat deaths are rising and polls show a softening of public backing for the eight-year war.
200th British fatality
The British army has suffered its 200th fatality in Afghanistan since the US-led invasion in 2001.
The soldier was injured in an explosion on Thursday and died on Saturday in a military hospital in England.
"The death of the 200th British serviceman in Afghanistan is deeply tragic news," Prime Minister Gordon Brown said.
Mr Brown, who is behind in opinion polls less than a year before parliamentary elections, has faced intense political pressure over Britain's role in Afghanistan in recent months.
Critics accuse him of sending too few troops to fight the Taliban with insufficient equipment, such as helicopters and armoured patrol vehicles.
'Repressive' law takes effect
Meanwhile, legislation allowing a husband to starve his wife if she refuses to have sex has been published in the official gazette and become law.
The original bill, stipulating how often a wife must have sex with her husband, caused outrage earlier this year, forcing Afghan President Hamid Karzai to withdraw it.
But critics say the amended version of the law remains highly repressive.
They accuse Mr Karzai of selling out Afghan women for the sake of conservative Shia support at next week's presidential election.
