KUNDUZ, Afghanistan, April 6 (Reuters) - A roadside bomb killed two Afghan election workers and one policeman and destroyed dozens of ballot papers on Sunday, police and an election official said, the day after an election that ended without any major violence despite Taliban threats.



Around 60 percent of eligible Afghan voters cast their ballots across the country in a presidential vote hailed as a success by Afghan and Western officials.



Although the Taliban failed to pull off major attacks on election day itself, some fear insurgents are preparing to disrupt the ballot-counting process which is due to take weeks in a country with basic infrastructure and a rugged terrain.



In the first such attack since polling closed on Saturday night, a bomb hit a car carrying election staff and ballot papers in Khanabad district of the northern Kunduz province, police said.



"The car carrying ballot papers from four polling stations was hit and all the materials were burnt," Amza Ahmadzai, an election official in Kunduz, told Reuters, adding that two staff and one policeman were killed.



The Taliban have condemned the election - designed to be Afghanistan's first democratic handover of power - as a U.S. backed sham. The incumbent, Hamid Karzai, is barred by the constitution from running again after 12 years in power.



There is no clear frontrunner but the three main candidates are former foreign ministers Abdullah Abdullah and Zalmay Rassoul, and former finance minister Ashraf Ghani.



The election came at a crucial time as most foreign troops prepare to go home after fighting the Taliban insurgency for more than a decade.