Q+A: Obama sends more U.S. troops to Afghanistan

(Reuters) - President Barack Obama has authorized an extra 17,000 U.S. troops for Afghanistan in an effort to halt worsening insurgent violence there.

Here are some key questions and answers linked to the deployment.

WHICH TROOPS WILL GO?

About 8,000 troops from the 2nd Marine Expeditionary Brigade from Camp Lejeune, North Carolina, will go to Afghanistan in late spring. About 4,000 soldiers from the U.S. Army's 5th Stryker Brigade, 2nd Infantry Division, from Fort Lewis, Washington state, will deploy in the summer. Another 5,000 support troops will also deploy, the Pentagon says.

The new forces will add to the 38,000 U.S. troops and approximately 30,000 military personnel from other nations, who form part of a NATO-led force, already in Afghanistan.

WHERE WILL THEY GO?

The Pentagon says the troops will be deployed to southern Afghanistan, where insurgent violence is worst. Britain, the Netherlands, Canada and other nations already have troops in southern Afghanistan, as does the United States.

WHAT WILL THEY DO?

Commanders say extra troops will allow them to hold territory once it has been cleared of insurgent fighters. Until now, they say, they have not had enough troops to maintain a presence in those areas and allow essential services to be provided and economic development to take place. Such projects will motivate ordinary Afghans to reject the Taliban, military commanders say.

WILL CASUALTIES GO UP?

Probably, at least in the short term. Senior U.S. officials have said that as the troops attempt to clear more areas of insurgents, there is a higher risk of casualties.

WHAT ARE THE OTHER RISKS?

Some independent analysts have questioned the wisdom of a major troop buildup. They have suggested that a larger foreign military presence runs a greater risk of being seen as an occupying force by ordinary Afghans.

Some analysts have also questioned whether such a major effort is necessary to achieve Washington's main goal of preventing al Qaeda from using Afghanistan to plot attacks against the United States.

(Editing by Patricia Wilson and Chris Wilson)

(Reporting by Andrew Gray)