A car bomb attack on an Afghan police station, followed by clashes, killed at least five people and wounded 33 people in eastern Afghanistan, bordering Pakistan, officials said Tuesday.

"At 0550 GMT (0120 GMT), terrorists detonated a car packed with explosives near a compound of the special forces in the police in the city of Khost," Interior Ministry spokesman Tariq Erian said.

Ghulam Dawood Tarhail, Khost police chief, told France Press that the device detonated by a suicide bomber was followed by two suicide car bombings and a nine-hour exchange of fire between seven attackers who were killed and the security forces.

Erian confirmed the end of the attack.

The Khost police chief announced that five policemen were killed and 33 people were wounded, including nine civilians.

No party has yet claimed responsibility for the attack.

Khost is the stronghold of the Haqqani network, the Taliban wing, to which the bloodiest specific attacks have been attributed, especially the truck bomb attack on the Green Zone in Kabul in May 2017, which left more than 150 people dead.

Kabul also witnessed violence Tuesday. Police spokesman Firdaus Framouz said in a statement that three civilians were killed and 10 wounded in a bomb placed under a car near the airport.

Afghanistan is witnessing an escalation of violence in recent weeks, at a time when talks are continuing between the Taliban and the Afghan government in an effort to end the ongoing conflict in the country for years.

Tuesday, the US envoy to Afghanistan Zalmay Khalilzad, who is visiting Qatar soon, tweeted that "the window for reaching a political settlement will not remain open forever."

In a separate statement, the State Department announced that Khalilzad was trying to persuade the two sides "to intensify their efforts and agree on a political roadmap" to end the conflict.

And she considered that "the two parties need an urgent agreement to reduce violence that leads to a permanent and comprehensive ceasefire."

Kabul has been asking the Taliban for a ceasefire for years, and the movement refuses to do so, fearing losing one of its most important cards in the negotiations.

According to the United Nations mission in Afghanistan, the number of civilian casualties has not decreased since negotiations began on September 12.

"The peace negotiations need some time to contribute to establishing peace," said Deborah Lyons, head of the mission, in a report.

"But all parties can immediately prioritize the talks and take additional, urgent, overdue measures to spare civilians from the severe harm," she added.

The total number of civilian casualties decreased by nearly 30 percent during the first nine months of 2020 compared to the same period last year, i.e. 2,177 civilians were killed and 3,822 injured, according to the United Nations.

This is due to the decrease in violence during the negotiations that preceded the start of the talks in Doha, but which have since resumed.

Between January and the end of September, 58 percent of civilian casualties were reported by "anti-government elements" such as the Taliban and the Islamic State, and 23 percent by Afghan forces, including aerial or ground bombardments, according to the United Nations.

The Taliban, in a statement, rejected the findings of the UN report.