By Hamid Shalizi and Jessica Donati
KABUL (Reuters) - The last two men in the race to become Afghanistan's next president on Thursday began a second round of campaigning ahead of the run-off election on June 14.
The election will take place at the height of the summer fighting season when the insurgency is at its most violent, stoking fears the Taliban may be more able to disrupt the vote after failing to prevent a high turnout in the first round.
"Our reaction to this process will be very strong and we will make (the election) fail," Taliban spokesman Zabihullah Mujahid told Reuters by telephone.
Fighting has intensified since the launch of the Taliban's summer campaign, which has claimed dozens of lives this week and included the capture by insurgents of a district in northern Badakhshan province.
During the three-day battle for Yamgan district, 25 police men were captured by rebels, provincial police chief Safi Ayaar told Reuters, adding that a group of elders was negotiating for their release.
The interior ministry played down concerns on Thursday, saying warmer weather was advantageous to both sides.
"The summer season is not only suitable to the enemies but to Afghan forces as well. They don't need tents, sleeping bags or heaters," Interior Minister Umer Daudzai told a conference.
Both contenders, former anti-Taliban Northern Alliance leader Abdullah Abdullah and former World Bank economist Ashraf Ghani, kicked off their campaigns in Kabul.
Reflecting concerns the Taliban may target large gatherings, Ghani told supporters no big rallies would be held this time.
"Our team will travel to all districts of Afghanistan and speak to them and show them we are in their service," he said.
Whoever succeeds President Hamid Karzai, who is constitutionally barred from a third term, will have to deal with the Taliban insurgency as most foreign troops leave this year and manage a rapid decline in financial resources.
Abdullah scored 45 percent the first round according to results published last week. Ghani, a former finance minister, trailed by almost 14 points with 31.6 percent.
But Ghani could gain a portion of votes in the run-off that splintered in the first round between candidates linked to the Pashtun majority. Abdullah is more closely identified with the minority Tajik community.
The election went to a run-off as none of the eight candidates who contested the initial round on April 5 secured more than 50 percent of the vote.
Both candidates ran against President Hamid Karzai in the 2009 elections during which over a million votes were thrown out as fraudulent. Ghani won only about 4 percent of the vote at the time and Abdullah dropped out, citing concerns about fraud.
More complaints of serious fraud were registered in the April 5 election than in 2009, but fewer votes were rejected this time, fuelling complaints by candidates that the bulk of those illegitimately cast were included in the final tally.
At his opening rally, Abdullah took a swipe at the election complaints commission, urging it to reform ahead of the run-off.
"We once again stress the need for transparency and better monitoring, and that's what we have suggested to the election commissions," he told supporters.
(Editing by Maria Golovnina and Ron Popeski)