KABUL, Afghanistan (AP) — A suicide bomber blew up a car packed with explosives near a busy market and a mosque in eastern Afghanistan on Tuesday, killing at least 89 people in the deadliest insurgent attack on civilians since the 2001 U.S.-led invasion.

The blast destroyed numerous mud-brick shops, flipped cars over and stripped trees of their branches, brutally underscoring the country’s instability as U.S. troops prepare to leave by the end of the year and politicians in Kabul struggle for power after a disputed presidential runoff.

Gen. Mohammad Zahir Azimi, the Defense Ministry spokesman, said the bomber detonated his explosives as he drove by the crowded market in a remote town in Urgun district, in the Paktika province bordering Pakistan. Azimi gave the death toll and said more than 40 other people were wounded.

Nearby hospitals were overwhelmed, and dozens of victims were transported over dangerous roads to the capital, Kabul.

Ahmad Shah, a gas station employee who rushed to the site to help, said he loaded dozens of people who were injured or killed into vehicles.

“I saw the smoke, and the town was burning. There were dead bodies everywhere,” he said outside a hospital in Kabul.

Associated Press video footage of the aftermath showed mounds of twisted debris and the charred shells of cars flipped over on top of one another.