Gates is visiting Afghanistan for the first time as defense secretary and has said defeating the Taliban is a top priority.
It is expected during talks with Afghan officials --including Karzai -- that Gates will reaffirm the U.S. commitment to Afghanistan and discuss ways of combating the resurgent insurgency.
Gates accused Afghanistan's western neighbor, Iran, of playing a "very negative" role in Iraq and the wider region, and he said Tehran appears to believe the U.S. has its hands full in Iraq.
Karim Rahimi, a spokesman for Karzai, said in Kabul today that the talks between Karzai and Gates will focus on security.
"The main aim of the talks -- the main issue of the talks -- is security in Afghanistan and in the region and the fight against terrorism, [as well as] support for the achievements that have been reached in Afghanistan," he said.
Gates Sees Increased Threat
He is also due to meet with NATO and U.S. commanders in Afghanistan to get an update on the security situation.
Gates flew to Kabul on January 15 from Brussels, where he discussed the situation in Afghanistan with NATO Secretary-General Jaap de Hoop Scheffer.
Gates told reporters after the meeting that the threat posed by the Taliban insurgents may increase in 2007.
"One of the subjects we have been talking about was the increased level of violence last year and some indications that the Taliban want to increase the level of violence in 2007," he said.
Afghanistan last year witnessed a record number of attacks by insurgent forces that led to the estimated death of some 4,000 people, including many civilians. Attacks by insurgents in Afghanistan usually increase in spring after the snows melt.
Call For More Troops
Today, the top U.S. commander in Afghanistan, Lieutenant General Karl Eikenberry, said NATO and U.S. forces are already taking steps to meet the threat. He said he does not anticipate any reduction this year in the approximately 20,000 U.S. troops in Afghanistan.
About half of them operate as part of the 33,000-strong International Stability and Assistance Force In Afghanistan (ISAF), which is spearheaded by NATO. The rest are involved in counterterrorism missions and also some of the training of the Afghan army.
The U.S. military said Gates will also meet today with U.S. troops that are stationed in the Afghan capital, Kabul. Later he is due to have a joint press conference with Karzai at the presidential palace.
Gates on January 15 accused Afghanistan's western neighbor, Iran, of playing a "very negative" role in Iraq and the wider region, and he said Tehran appears to believe the U.S. has its hands full in Iraq.
Iran has expanded its ties with Afghanistan since the fall of the Taliban government in 2001.
Kabul has said in the past that it is ready to play a role in reducing tension between its ally -- the United States -- and neighboring Iran.
A U.S. military vehicle damaged by insurgents near Kandahar (epa)
HOMEGROWN OR IMPORTED? As attacks against Afghan and international forces continue relentlessly, RFE/RL hosted a briefing to discuss the nature of the Afghan insurgency. The discussion featured Marvin Weinbaum, professor emeritus of political science at the University of Illinois at Urbana-Champaign, and RFE/RL Afghanistan analyst Amin Tarzi.
Listen to the entire briefing (about 83 minutes):Real Audio Windows Media
RFE/RL's coverage of Afghanistan
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