Obama in Afghanistan

[Update 1:59 p.m. ET] U.S. President Barack Obama made a surprise visit to Afghanistan on Friday, personally delivering holiday greetings to U.S. troops stationed there and promising continued full support in the war against Taliban and other extremists. More on Obama's visit and his scheduled meeting with Karzai

Watch an excerpt from the speech:

Or read a recap of the speech as it was happening:
[Update 1:28 p.m. ET] Obama wraps up his address to the troops.

[Update 1:26 p.m. ET] Obama cites the story Staff Sgt. Salvatore Giunta, the recent recipient of the Medal of Honor for his actions in Afghanistan.

[Update 1:23 p.m. ET] Although Americans have their differences, Obama says, there is no hesitation back home "to give support to our men and women in the military service ... We're going to spare no effort to make sure your families have support as well."

[Update 1:19 p.m. ET] Obama acknowledges the U.S. war casualties in Afghanistan: "We know their memories will never be forgotten," he says, but because of their sacrifice, "We look forward to a new phase next year, a transition to Afghan responsibility."

[Update 1:14 p.m. ET] Obama says that as president, "I have no greater responsibility than keeping the American people secure.  I could not do that ... without the extraordinary service each and every one of you perform each and every day. ... We are here to say thank you.  I also want to say thank you to your families back home."

[Update 1:09 p.m. ET] President Obama begins to address the troops at Bagram, saying "I want to make sure I could spend a little time this holiday with the men and women of the finest fighting force the world has ever known." WATCH LIVE

[Original post] U.S. President Barack Obama arrived in Afghanistan on Friday on a surprise visit to U.S. troops.

The president, who is expected to remain on the ground there for roughly three hours, is slated to address troops at Bagram Airfield. Most of the troops are with the Army's 101st Airborne Division. Representation from components of all services will also be in attendance.

He will also visit wounded troops at a hospital on the base, according to reporters traveling with Obama. The president will meet with a total of eight patients - five soldiers and three civilian contractors. He will award four Purple Hearts.

Obama was originally scheduled to travel to Kabul to meet with Afghan President Hamid Karzai and greet U.S. embassy staffers, but will stay at Bagram because of poor weather conditions. Obama will, however, speak to Karzai via secure videoconference. National Security Adviser Tom Donilon, Ambassador Karl Eikenberry, and Gen. David Petraeus, the top U.S. commander in Afghanistan, will also participate in the meeting.

It is unclear if revelations about U.S. concerns with the Karzai government recently publicized by the group WikiLeaks will be discussed.

Almost a year ago, on December 1, 2009, Obama announced his new strategy for Afghanistan that would see some forces coming home as soon as July 2011. Officials have said the goal is to end combat operations in Afghanistan in 2014. A major U.S. military review of the war in Afghanistan is due this month.

Obama has made surprise visits to Afghanistan in the past. Once, earlier this year in March, he slipped into Bagram near Kabul under the cover of darkness. He met with about 2,000 troops at the U.S. base and told them their work is significant to security at home.

His first trip to Afghanistan came in July 2008, months ahead of the presidential election.