President Karzai, the frontrunner, flew to the western city of Herat to address thousands of supporters.

Former Foreign Minister Abdullah Abdullah travelled to the the central province of Dai Kundi.
 

The other leading candidate, Ghani Ahmadzai went to Zabul after a TV debate between the three was cancelled.

On Thursday Mr Ghani criticised his rivals in next week's elections for withdrawing from a television debate.
 

It was the second attempt to bring together Mr Ghani, incumbent President Hamid Karzai and former Foreign Minister Abdullah Abdullah.
 

But when the president pulled out of the debate, Mr Abdullah followed suit.

President Karzai also withdrew from a similar debate last month, arguing that the television company hosting it was biased against him.
 

'High tension'

"Today is a sad day for democracy in Afghanistan," Mr Ghani told reporters. "A democratic society cannot function without a democratic debate."
 

President Karzai has been campaigning in Herat

The latest debate was cancelled because President Karzai, who has led Afghanistan since 2001, again argued that the private TV station which was to have hosted it was biased against him.
 

Mr Ghani, a former finance minister, said that a televised discussion would have offered a chance to reassure the nation that politicians would not call for demonstrations against the results, which are due on 17 September.
 

"The environment is uncertain and tension is high," he said, accusing both campaigns of raising the possibility of "force" being used to challenge the results.
 

"A debate would have contributed to calm down the country and create the necessary environment for civic politics, the only kind of politics that is permissible and desirable," he said.
 

Meanwhile officials have told the AFP news agency that 10% of voting stations could be closed ahead of Thursday's vote because of safety fears.
 

The Independent Election Commission (IEC) said the total number of stations could be as low as 6,200, down from earlier expectations of close to 7,000.