Visiting U.S. Defense Secretary Chuck Hagel and Afghan President Hamid Karzai are due to hold talks in Kabul.
Hagel is making his first visit to Afghanistan since becoming U.S. defense secretary.
Hagel and Karzai are expected to discuss issues including Karzai’s recent order demanding the withdrawal of U.S. Special Operations forces from Wardak Province over allegations that Afghans working with the commandos have been involved in abuse and torture.
The agenda is also expected to include security issues connected to the planned withdrawal of all foreign combat forces from Afghanistan by the end of 2014.
A press conference due to take place following the talks has been canceled, reportedly due to security concerns.
Withdrawals of tens of thousands of forces are getting under way this year.
In comments made earlier on March 10, Karzai said that representatives of the Taliban have been holding talks "on a daily basis"
with the U.S. government.
The United States has not responded to Karzai's statements.
Hagel's visit to Afghanistan comes after a Taliban suicide bomber on March 9 blew himself up outside the Afghan Defense Ministry in Kabul, killing nine Afghan civilians.
The Taliban said the attack was meant as a message to Hagel to show that the militants remain a force.
Hagel, who took office at the end of February, said he heard the explosion.
"I wasn't sure what it was," Hagel told reporters. "I was in a briefing. But we're in a war zone. I've been in war. So we shouldn't be surprised when a bomb goes off or there's an explosion."
In another incident on March 9, in the eastern city of Khost, eight children and at least one police officer were killed when a suicide bomber detonated explosives at a checkpoint.
Hagel, a decorated U.S. military veteran who was wounded in battle in the Vietnam War, said the war would continue as part of the effort to enable the Afghan people to develop a democracy.
“We’re at war," he said. "The war didn’t stop, and we have a war here. That’s just a reality. We’re going to continue to work with the Afghans and our coalition partners to fight that war and to assure that the Afghan people have every ability and right to develop their own country, their own way, in a democracy.”
Washington and Kabul are seeking to negotiate resolutions to several contentious issues.
A planned ceremony on March 9 to mark the handover to Afghanistan of the main U.S.-run detention center in the country was again delayed after the two sides could not reach a final agreement.
The transfer of Bagram prison, originally planned to occur in 2009, has been repeatedly delayed because of disagreements over control of detainees.
The Afghan government wants full control of all detainees, saying the matter is an issue of national sovereignty.
The U.S. is seeking safeguards to prevent the release of prisoners that Washington considers a threat.
Washington and Kabul are also continuing to negotiate a bilateral security agreement that would regulate U.S. operations in Afghanistan beyond 2014.
Some 66,000 U.S. troops and 30,000 soldiers from NATO and other allied forces are still based in Afghanistan. More than half of the U.S. deployment is planned to withdraw this year.
With reporting by AP, Reuters, and dpa