Two journalists working for The Associated Press have been shot in Afghanistan, one of them fatally, the news agency said Friday.
The Associated Press said the slain journalist was Anja Niedringhaus, 48, an internationally acclaimed German photographer. She was shot in the country's eastern Khost province.
The second journalist targeted by the gunman was Kathy Gannon, a Canadian reporter based in Islamabad, the AP said. She is said to be in a stable condition and is receiving medical care.
"Anja and Kathy together have spent years in Afghanistan covering the conflict and the people there," said AP executive editor Kathleen Carroll, speaking in New York. "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."
In a letter to AP staff Friday morning, chief executive Gary Pruitt also praised her courage and skill, describing her as "spirited, intrepid and fearless, with a raucous laugh that we will always remember."
The two women were traveling in their own car in a convoy of election workers delivering ballots in Khost province, protected by the Afghan National Army and Afghan police, the news agency said.
A unit commander walked up to their car as it waited to move, yelled "Allahu akbar" - "God is great" - and opened fire on them in the back seat, the AP said. He then surrendered to the other police present.
The reason for the attack is unclear, but police have arrested the suspected shooter and the case is under investigation, Baryalay Rawan, a spokesman for the Khost provincial governor, told CNN.
The attack came amid heightened security on the eve of Afghanistan's presidential and provincial elections.
The third presidential vote since the fall of the Taliban in 2001, this year's elections mark the first democratic handover of power in the fragile country, with current President Hamid Karzai - who is term-limited by the constitution - handing over the reins.
The Taliban have vowed to disrupt the elections and punish anyone involved in them.
A series of attacks in the capital, Kabul, and elsewhere has marred the run-up to the elections.
On Wednesday, a suicide bomber blew himself up at the entrance gate to the Interior Ministry in Kabul, killing six Afghan police officers, Interior Ministry spokesman Sediq Sediqqi said. The Taliban claimed responsibility for the attack.
A day earlier, a provincial council candidate and nine of his supporters were killed by the Taliban in northern Sar-e-Pul province, said the province's deputy police chief, Sakhidad Haidari.
Other journalists killed
Last month, the names of two more journalists were added to the list of those killed in Afghanistan.
Sardar Ahmad, one of Afghanistan's most prominent journalists and a senior reporter for Agence France-Presse, was among nine people killed in an attack on the Serena Hotel in central Kabul.
That attack came less than two weeks after Swedish Radio correspondent Nils Horner was shot dead in broad daylight on a Kabul street.
In his letter to AP staff, Pruitt said: "As conflict spreads throughout regions of the world, journalism has become more dangerous. Where once reporters and photographers were seen as the impartial eyes and ears of crucial information, today they are often targets."
The Committee to Protect Journalists highlighted the risks faced by journalists, particularly women, in Afghanistan in a piece published in February.
Some fear those risks may increase as the planned withdrawal of NATO combat forces, including U.S. troops, looms at the end of the year.
The NATO-led International Security Assistance Force had just over 51,000 troops, from 48 different countries, in Afghanistan as of Tuesday. Of those, the vast majority - about 33,500 - are from the United States.
Karzai has refused to sign an agreement to keep foreign security troops in the country after 2014.
But Gen. Philip Breedlove, NATO's supreme allied commander Europe, told CNN's Christiane Amanpour this week that he anticipates international forces will remain in Afghanistan after the currently scheduled withdrawal.
"I think you will see a very large ISAF combat mission changed to a smaller but continued resolute support, train, advise and assist mission at the end of the year," he said. "NATO's mission doesn't end (after 2014); NATO's combat mission ends, but our train, advise, assist mission begins, and this is very important to remember."
The three leading presidential candidates - Abdullah Abdullah, Zalmai Rassoul and Ashraf Ghani - have told CNN that they are in favor of signing a deal.
Abdullah, who was a vocal critic of the Taliban during their years in power, was a previous Karzai ally and served in his government as foreign minister. But in later years, he has been a thorn in the side of the outgoing President. He is seen as a relatively liberal candidate and advocate of women's engagement in public life.
Rassoul is seen as the establishment candidate. A Karzai ally, he received the backing of the current President's brother, Qayum, who withdrew his candidacy and endorsed the former foreign minister. Rassoul has a reputation for honesty, despite his years in an administration plagued with accusations of graft.
The third key contender, Ghani, is a former U.S. citizen and academic who gave up his passport to run for the Afghan presidency in 2009. He is seen as a moderate, with experience in development, but his past links to the United States may lessen his chances if voters see him as an outsider.
NATO Secretary General Anders Fogh Rasmussen, speaking Wednesday in Belgium, said the latest briefings from NATO commanders show that despite the Taliban's threats, overall violence across Afghanistan "is lower now than at any time during the last two years."
Rasmussen praised the work of Afghan security forces, which have taken over many responsibilities from the NATO-led International Security Assistance Force, saying they had "demonstrated commitment, courage and professionalism" during preparations for the elections.