The frontrunners for Afghanistan’s presidency, the incumbent Ashraf Ghani and chief executive Abdullah Abdullah, have both declared victory, echoing an election crisis five years ago when competing claims by the two men led to months of turmoil.

The country’s Independent Election Commission is gathering votes from Saturday’s poll. If no candidate wins more than half, a runoff vote will be held between the top two.

“Our votes are the highest in the election, and the election will not go to the second round,” Abdullah said at a press conference in Kabul on Monday.

Ghani’s running mate, Amrullah Saleh, said Ghani had won a clear first-ballot victory, without offering evidence. “The information that we have received show that 60-70% of people voted [for] us,” Saleh was quoted by the news outlet VOA as saying.

Ghani and Abdullah were also the top two candidates in the previous election in 2014, leading to months of confusion as both men accused each other of fraud. The US eventually stepped in to broker a power-sharing deal under which Ghani became president and Abdullah accepted the new post of chief executive.

Abdullah was also involved in a months-long election dispute in 2009 when he challenged the victory of the then-incumbent, Hamid Karzai. Afghan presidential candidates have a pattern of assembling competing coalitions of regional and ethnic chieftains, and accusing rival camps of organising fraud in far-flung districts under the control of their supporters.

The chief executive of the electoral commission, Habiburrahman Nang, told a press conference that no candidate had the right to declare himself the winner before the results are tallied.

Preliminary results are not expected before 19 October and final results not until 7 November.

Abdullah said he would accept only votes that were filed with biometric voter verification. Problems with scanning machines had led the commission to also accept votes without scanning fingerprints.

Foreign countries that have troops in Afghanistan are wary of yet another destabilising election dispute.

Boasting of victory before the election commission had even counted votes was unhelpful, said the Czech Republic ambassador to Afghanistan, whose country has 350 soldiers in the US-led Nato force that supports the government. “It’s pushing the election commission into murky water. [The candidates] should respect the institutions,” Petr Stepanek said.

The winner would have a stronger position to conduct any negotiations with the Taliban, aimed at ending the country’s 18-year war.

Tight security ensured the election was conducted in relative calm, with only small-scale attacks by the Taliban. At least 2.2 million people voted, with more to be gathered, the commission said.

Ballot boxes are being transported from remote areas to Kabul for counting and the process can be dangerous. Thirteen election staff members have been kidnapped since Saturday by the Taliban, and 11 others were wounded on election day, the election commission spokesman, Abdul Aziz Ibrahimi, said.

The Taliban said the low turnout underlined that the election was illegitimate and that Afghan people did not accept “foreign imported processes”. The group threatened attacks leading to polling day, causing many voters to stay home.