The two leading candidates in Afghanistan's presidential election are alleging ballot fraud.
Former Foreign Minister Abdullah Abdullah and former Finance Minister Ashraf Ghani are expected to compete in a runoff after preliminary results from the April 5 election showed neither gained the 50 percent needed for a first-round victory.
Final official results are still two weeks away.
But Abdullah on April 27 alleged there was widespread fraud in the vote and insisted he won the first round outright.
Ghani also alleged fraud, saying there was "no clear winner" in the first round.
Preliminary results released on April 26 showed Abdullah with 44.9 percent of the first-round vote and Ghani at 31.5 percent, with Zalmai Rasul a distant second at 11.5 percent.
Abdullah quit the race, alleging fraud, after finishing second to incumbent President Hamid Karzai in the first round of the country's 2009 presidential election.
The runoff is expected sometime after May 28.
The winner will succeed outgoing President Hamid Karzai in the first democratic transition of power in Afghanistan.
Based on reporting by AFP and dpa