KABUL — A bomb blast killed two U.S. Marines in Afghanistan's dangerous south, where thousands of American troops have deployed in a massive operation to oust Taliban fighters from the country's opium poppy region, officials said Sunday.
Some 4,000 Marines moved into Helmand province this month, the largest Marine operation in Afghanistan since the 2001 U.S. invasion. They have met little head-on resistance but remain vulnerable to guerrilla tactics like suicide and roadside bombs.
"These terrorist attacks are hard to prevent, can be carried out by a few individuals, and do not require a military force capable of confronting the Marines," said Arturo Munoz, an expert on the tribal environment in Helmand province with the Washington-based RAND Corp.
"I would expect the Taliban to avoid pitched battles with the Marines in order to avoid a large number of casualties," he said. "This does not mean they will avoid violence."
The two Marines were killed Saturday in Helmand. Military officials did not release any other details nor give a specific location. The military initially reported four Marines had died but later corrected the figure, saying the deaths were mistakenly double-counted.
The American casualties come after eight British deaths in Helmand in a 24-hour period ending Friday, triggering debate in Britain about its role in Afghanistan. Britain has now lost more troops in Afghanistan than in Iraq.
In an interview broadcast Sunday, President Barack Obama called Britain's contribution critically important and said U.S. and British troops face a difficult summer ahead of elections in Afghanistan late next month.
"We've got to get through elections," Obama told Sky News. "The most important thing we can do is to combine our military efforts with effective diplomacy and development, so that Afghans feel a greater stake and have a greater capacity to secure their country."
British Prime Minister Gordon Brown has said fighting the Taliban in Afghanistan will help keep extremist groups from launching attacks inside Britain. And he told Afghan President Hamid Karzai in a telephone call Sunday that Britain would stand "shoulder-to-shoulder with the people of Afghanistan for the long haul," according to a statement by the Afghan presidency.
The embattled prime minister told his troops in an interview Sunday with the British military radio network that it was proving to be a "difficult summer" in Afghanistan but that operations in Helmand were making "considerable progress" toward defeating the Taliban.
But in an editorial Sunday, The Observer newspaper predicted the British public will soon decide the war is not worth the casualties.
"Lives saved by bringing soldiers home will seem a surer benefit than the unproven hypothesis of preventing terrorism with a war thousands of miles away," the newspaper said.
Another American service member died Friday in the U.S. of wounds suffered in Afghanistan in June, said Lt. Cmdr. Christine Sidenstricker, who confirmed the deaths of the two Marines.
The three deaths bring to 104 the number of U.S. troops killed in Afghanistan this year, a record pace. Last year 151 U.S. troops died in the country. Overall, 193 international troops have died in Afghanistan this year, according to an Associated Press count based on official announcements.
Obama ordered 21,000 additional U.S. troops to Afghanistan earlier this year to help put down an increasingly violent Taliban insurgency. Some 10,000 Marines and 4,000 soldiers from the Stryker Brigade _ the 5th Brigade, 2nd Infantry Division based in Fort Lewis, Wash. _ are deploying in the south, the Taliban's spiritual birthplace and stronghold.
The troops will help provide security for the Aug. 20 election, when Afghans will choose a president and provincial councils, and help train army and police units that the U.S. hopes one day can provide security for the country. By fall, a record 68,000 U.S. troops will be in Afghanistan.
Violence flared elsewhere around the country over the weekend, illustrating again that security is deteriorating. At least 22 people were killed, including seven police officers, officials reported on Sunday.
_ In southern Uruzgan province, international troops and Afghan police killed 12 militants in a gunbattle Saturday, police spokesman Mohammad Musa said.
_ In Logar, four policemen died when a roadside bomb hit their car in Charkh district Saturday, said provincial police chief Gen. Mustafa Mosseini.
_ In Helmand, two police were killed in a roadside bombing in the Helmand provincial capital of Lashkar Gah late Saturday, said Dawood Ahmadi, the governor's spokesman.
_ In a gunbattle in eastern Paktia province between insurgents and Afghan police, two militants and one police officer were killed, said Rahullah Samon, a spokesman for the governor.
_ In eastern Kunar province, one civilian was killed and five wounded when shells from a gunbattle between insurgents and Afghan and coalition forces hit a house. Provincial Police Chief Gen. Abdul Jalal Jalal said it was unclear which side fired the shots that hit the house.
Associated Press writers Amir Shah in Kabul and Noor Khan in Kandahar contributed to this report.