A Pulitzer-prize winning photographer was killed and one reporter was left injured after a policeman in eastern Afghanistan opened fire in to their car, Friday.

Photographer Anja Niedringhaus and veteran correspondent Kathy Gannon, both from the Associated Press news agency and covering the presidential elections, were  travelling with a group of election workers to the Khost city. They were accompanied by Afghan security forces to protect them.

A unit commander identified as Naqibullah went near the car and opened fire with an AK-47, a freelance videographer who witnessed the incident told the Associated Press. He then surrendered himself to the police . Interior ministry of Afghanistan confirmed the arrest.

Niedringhaus, 48, died on the spot and Gannon, 60, was wounded in the wrist and shoulder. Medical authorities said her condition was stable. NATO's regional command in charge of Eastern Afghanistan was asked to offer assistance to help airlift Gannon for treatment, reports ABC News.

"Anja and Kathy together have spent years in Afghanistan covering the conflict and the people there. Anja was a vibrant, dynamic journalist well-loved for her insightful photographs, her warm heart and joy for life. We are heartbroken at her loss," AP Executive Editor Kathleen Carroll said.

This was the third attack on journalists in Afghanistan within a month. Nils Horner, a 52-year-old Swedish-British radio reporter was killed in the capital city Kabul March11. Shortly after that a reputed Afghan reporter Ahmad Sardar was fatally shot along with his wife and two children at a Kabul hotel. He was in the hotel to celebrate the Persian New Year, reports The Guardian.

Both Niedringhaus and Gannon are veterans of the Afghan war and have together covered the Afghan turmoil since 2001.They embedded with the  military and Afghan police several times and covered the war from the civilians' viewpoint.

 Killing of the AP journalists came just one day before the critical national election in Afghanistan. Over 350,000 security personnel have been deployed throughout the country.