KABUL (AFP) - Shocked colleagues of Sardar Ahmad, the senior reporter in AFP's Kabul bureau, Friday mourned the loss of a charming and talented journalist with a deep, nuanced understanding of Afghanistan's wrenching conflict.

Mr Ahmad, 40, was shot dead along with his wife Humaira and two of their three children - a girl and boy - when gunmen attacked the Serena hotel in the Afghan capital on Thursday evening.

An AFP staff photographer identified the four bodies at a city hospital on Friday, and said the family's infant son was undergoing emergency treatment after suffering serious wounds.

"This is an immensely painful and enormous loss for Agence France-Presse," AFP chairman Emmanuel Hoog said.

He described Mr Ahmad as a "dedicated and courageous journalist, a cornerstone of our team in Afghanistan who delivered, every day, exceptional coverage of the news in extremely difficult conditions".

A statement from Afghan President Hamid Karzai said Mr Ahmad's killing was "a big crime... heartbreaking and sorrowful".

Four teenage gunmen with pistols hidden in their socks managed to penetrate several layers of security to attack the luxury hotel on the eve of Nawroz, the Persian New Year which is a major holiday in Afghanistan.

The Serena attack was claimed by the Taleban, who have vowed a campaign of violence to disrupt the April 5 election that will decide a successor to President Hamid Karzai.

Hired in 2003 to cover daily briefings by the US-led coalition at Bagram airbase, two years after the invasion that drove out the Taleban regime, Mr Ahmad went on to cover all aspects of life, war and politics in his native country.

He was known among his colleagues for his wit, charm and ebullience. His time covering the briefings at Bagram allowed him to achieve an impressive level of fluency in English - and a distinctive American accent.

Mr Ahmad was a specialist in security issues, with strong contacts on both the government and Taleban sides, allowing him to file balanced stories on the complex conflict wracking Afghanistan.

"It is thanks to journalists like Sardar that the international media can cover the Afghan tragedy. The entire agency and its worldwide network is in mourning today," said AFP's global news director Philippe Massonnet.

Gilles Campion, AFP's Asia-Pacific regional director, described Mr Ahmad as one of the agency's best journalists in Afghanistan and "a beloved member of our team".

"During the 11 years he spent with AFP in Kabul, he always exercised immense courage and objectivity when reporting, despite the risks faced by journalists in that country."

Over the past decade Mr Ahmad filed dozens of stories charting life after the fall of the Taleban, the boom in opium, the challenges of rebuilding a war-shattered country, the elections of 2004 and 2009.

He was also a versatile reporter with an eye for unexpected stories that opened a window on life in Afghanistan away from the bombs and blast walls.

Beneath his tough, good-humoured exterior he had a passion for Afghan poetry and music.

In quiet moments he was known to turn the office TV to the Afghan version of Pop Idol to listen happily to young performers singing old songs of love and separation.

His last feature for AFP, filed on Tuesday, was about a lion called Marjan, rescued by animal welfare officials from living on a rooftop in Kabul. That was a follow-up to a story Mr Ahmad himself broke last year, generating headlines around the world.

He wrote in the feature: "Marjan is named after a famous half-blind lion who lived at Kabul zoo and became a symbol of Afghanistan's national survival after living through coups, invasions, civil war and the hardline Taleban era before dying in 2002."

Mr Ahmad's second-last story, the day before, covered a threat by the Taleban to attack polling staff, voters and security forces ahead of the April 5 election.

Outside AFP, Mr Ahmad showed his entrepreneurial bent by founding Kabul Pressistan, a successful local news agency that has provided fixing and translation services for numerous foreign reporters coming to Kabul.

He was also a devoted family man, leaving the office every Friday lunchtime to cook at home for his beloved children.

Phil Chetwynd, the editor-in-chief of AFP, said his death was an "unspeakable tragedy".

"Sardar was not only among the very finest journalists in Afghanistan, but also a wonderfully optimistic and engaging personality," Mr Chetwynd said. "He has been the pillar of our bureau for the past decade and a great friend to many AFP colleagues."