KABUL, Afghanistan  A British journalist embedded with an American unit in Helmand Province was killed along with a Marine when their vehicle struck a roadside bomb, the British Defense Ministry reported Sunday. It was the second time in two weeks that a Western journalist had been killed on an embedded assignment, underscoring the increased risk on the roads as military operations intensify in Afghanistan.
The journalist killed was Rupert Hamer, 39, the military correspondent for The Sunday Mirror newspaper, who was accompanying a United States Marines patrol northwest of the town of Nawa on Saturday. The dead Marine was not identified pending notification of next of kin, and United States officials would release no details about the episode.
The British government reported that four other United States Marines were seriously wounded by the bomb, and that a photographer in the vehicle, Philip Coburn, 43, was seriously wounded but was in stable condition at a military hospital in the area.
Mr. Hamer was only the second Western journalist killed while embedded with American or allied troops in Afghanistan since 2001. The first was on Dec. 30, when the Canadian journalist Michelle Lang was killed along with four Canadian soldiers in Kandahar Province when their vehicle hit a roadside bomb.
In August, Gen. Stanley A. McChrystal, the American commander in Afghanistan, outlined in an assessment he made to President Obama the need for troops to take a more active role, and since then the tempo of patrols and missions outside of bases has greatly increased.
So have military casualties: The International Security and Assistance Force, as the American-led alliance is called, lost 520 soldiers, mostly from roadside bombs, last year  far more than the 295 who died in Afghanistan in 2008, according to icasualties.org, an independent Web site that tracks military deaths in Afghanistan and Iraq. American and British troops had the majority of casualties.
The fighting and bombing have continued even in the midst of the normally severe Afghan winter, which has recently been unusually mild.
General McChrystal pointedly said that the days were over when Afghanistan was “a cyclical kinetic campaign based on a set ‘fighting season.’ ” Rather, he said, “It is a continuous, yearlong effort.”
“The more coalition forces are seen and known by the local population, the more their threat will be reduced,” General McChrystal wrote, criticizing the NATO coalition for in the past being “preoccupied with force protection.”
The intensified military campaign has also meant that more journalists have come here to cover it, often finding out firsthand the heightened risks that troops have been facing.
“Afghanistan is becoming a more dangerous place as the war ramps up and the U.S. comes in and begins an increase in troop numbers,” said Bob Dietz, Asia program coordinator for the Committee to Protect Journalists. He said that unlike most countries, where journalists who were killed were local people, “What we’re seeing is a large number of non-Afghan journalists dying.”
In all, 18 journalists have been killed since the American-led invasion of Afghanistan in 2001  12 of them foreigners. But until the past two weeks, none of the other foreigners had been killed while accompanying American or British troops, according to data compiled by the Committee to Protect Journalists.
In recent months, embedded journalists have frequently reported that their assignments in Afghanistan have been much more dangerous than previously. “We had contact every day; every day we have been shot at,” said Franco Pagetti, an Italian news photographer with the agency VII, who just returned from two weeks in the Korengal Valley in Kunar Province, where he accompanied a United States Army infantry unit.
The Brussels-based International Federation of Journalists released a statement saying that Mr. Hamer’s death “shows that Afghanistan remains one of the world’s most dangerous reporting assignments.” It continued: “Traveling with the Army does not lessen the risk to reporters. Indeed, as this tragedy shows, it can put journalists directly in the firing line.”
Prime Minister Gordon Brown of Britain said he was “deeply saddened by this tragic news.” The Sunday Mirror’s editor, Tina Weaver, praised Mr. Hamer, who was a father of three young children and who had made five trips to Afghanistan to report on the war, according to a statement that the paper released. “Affectionately known as Corporal Hamer in the office, he was a gregarious figure, a wonderful friend who was hugely popular with his colleagues,” Ms. Weaver said.
In Tarinkot, the capital of Uruzgan Province, three Afghan aid workers employed by a German relief agency, GTZ, were killed when the pickup truck that they were in struck a landmine on Sunday, said the provincial police chief, Juma Gul Himat.
British officials have said that a roadside bomb in southern Afghanistan killed a veteran British war correspondent and a US Marine yesterday.

Britain's Defense Ministry says Rupert Hamer, the defense correspondent for the Sunday Mirror  newspaper, was killed while accompanying Marines on patrol in the Helmand province. Photographer Philip Coburn was seriously wounded by the makeshift bomb, as were four other Marines.

''The Daily Mirror'' said that Hamer was a journalist with them for 12 years, and that this was his fifth trip to Afghanistan. Hamer is believed to be the first British journalist to be killed in the Afghan conflict. Prime Minister Gordon Brown released a statement expressing sympathy for his family, friends and colleagues. He was survived by a wife and three children.

Officials retracted earlier reports that an Afghan soldier was among those killed.

Hamer is the second journalist killed in Afghanistan in as many weeks. Canadian journalist Michelle Lang was killed on December 30, also by a roadside bomb.