Kabul, AP—Hundreds of Afghans took to the streets Saturday to protest against alleged fraud in last week’s presidential runoff, forcing a closure of the airport road amid escalating tensions over what Western officials had hoped would be a smooth transfer of power.

Former Foreign Minister Abdullah Abdullah, who is running against Ashraf Ghani Ahmadzai, a former finance minister, has accused electoral officials and others of trying to rig the June 14 vote against him.

Abdullah announced this week that he was severing ties with the Independent Election Commission and would refuse to recognize any results it releases. He also suggested that the UN step in, an idea supported by President Hamid Karzai, who is constitutionally barred from seeking a third term.

The IEC’s official timetable says initial results are due on July 2.

Around a thousand demonstrators gathered in Kabul to protest against the electoral commission, accusing it of fraud and chanting: “Our vote is our blood and we will stand up for it!”

Hundreds of anti-riot police surrounded the demonstration, which was peaceful.

“We gather today to protest against the election commission, which is not an independent commission at all. They are conducting fraud for a specific candidate,” said Mohammed Ghani Sharifi, a 23-year-old protester. “The people are so upset and they cannot tolerate such fraud because the people took risks to cast their votes.”

While the vote was relatively peaceful, the Taliban had warned people not to participate and carried out a handful of attacks in different parts of the country.

In a separate demonstration, hundreds of protesters marched from the northern part of the capital toward the airport, where they were stopped by a police roadblock that closed the road, preventing anyone from entering or leaving Kabul’s international airport.

“This is not about who becomes the leader of the country, but our protest is because of the fraud. No fraud should have happened for either candidate,” said Mohammed Essa, 23, who took part in the second protest, which was also peaceful.

“This is just the beginning of our protests,” he added.

The UN representative to Afghanistan, Nicholas Haysom, told a press conference that people had a “democratic right” to protest while urging them to remain peaceful and “refrain from inflammatory statements.”

Afghanistan’s next president is expected to sign a long-delayed security pact to allow nearly 10,000 American troops to remain in the country after most foreign forces withdraw by the end of the year. Both candidates have promised to sign the pact, but the next president must be sworn in first.

Earlier on Saturday, a suicide car bombing in Kabul aimed at a senior government official killed one civilian and wounded three others but did not harm its apparent target, Afghan security officials said.

Kabul police spokesman Hashmat Stanikzai said the bomber detonated his explosives-laden vehicle alongside the armored car of Mohammed Masoom Stanikzai, a senior official in the High Peace Council, a government body tasked with peace talks with the Taliban insurgency. The two men are not related.

Shafiullah, a police officer at the scene, said Stanikzai, who also serves as an adviser to President Hamid Karzai, was not harmed because he was traveling in an armored car. He said that while the explosion was “very strong” it took place early in the morning when the streets were relatively empty. Like many Afghans, the police officer only has one name.

No group claimed responsibility for the attack, but the Taliban frequently launch suicide attacks against Afghan civilians, government officials and security forces.

In the western Herat province, one civilian was killed and another was wounded when their vehicle struck a roadside bomb, provincial police spokesman Raouf Ahmadi said, adding that the two were on their way to the district bazaar.