KABUL (AP) ― U.S. Secretary of State Hillary Rodham Clinton is encouraging Afghanistan’s wary leadership to keep up Taliban reconciliation efforts and boosting counterterrorism cooperation with Pakistan as the Obama administration presses ahead with troop withdrawal plans.

Clinton arrived in Kabul late Wednesday on an unannounced visit and was scheduled to see President Hamid Karzai, other top Afghan officials and civic leaders on Thursday. Her trip came after Karzai expressed frustration with attempts to woo Taliban fighters away from the insurgency amid increasing attacks by the Taliban-allied, Pakistan-based Haqqani network.

Clinton was also to underscore the importance of linking Afghanistan to its neighbors, a consideration for a regional conference in Istanbul in early November, U.S. officials said.

The U.S. sees a political settlement with the Taliban as key to ending the war and is pushing Karzai to lead and expand a reconciliation drive, although the Taliban has indicated no public interest in such a deal. A secret U.S. effort to spark negotiations earlier this year angered Karzai.

The goal of reconciling fighters who renounce al-Qaida and violence and embrace Afghanistan’s constitution was dealt a major blow with the assassination last month of elder statesman Burhanuddin Rabbani, who was leading Karzai’s outreach. Rabbani was killed when he greeted a suicide bomber posing as a Taliban emissary bearing a reconciliation message.

A senior U.S. official said Clinton would emphasize that the U.S. remains committed to Afghan reconciliation and understands the difficulties that that process has undergone since the assassination. The official spoke on condition of anonymity to preview Clinton’s meetings.

Karzai has cited the killing as a reason why peace efforts are futile. He lamented recently that although he wants to continue, neighboring Pakistan should be in the lead since the Taliban high command lives there. In addition, spectacular attacks ― like one last month on the U.S. Embassy compound and the headquarters of the U.S.-led NATO forces in Kabul ― by the Haqqani network have dented enthusiasm for the push.

The U.S. official said the Obama administration is sympathetic to Karzai’s desire for Pakistan to do more and that Clinton would talk with Karzai about the need for Pakistan to put additional pressure on the Haqqani network.

Over the weekend, militants tried but failed to blast their way into an American base in eastern Afghanistan, striking before dawn with rocket-propelled grenades and a car bomb. The Taliban claimed responsibility for the attack in a text message sent to the Associated Press.

NATO says such spectacular strikes, many of them perpetrated by the Haqqani network, are actually down from past years. But assassinations have increased 60 percent for the same period with 131 people killed so far this year.

In addition to reconciliation, Clinton will also be pressing the Afghans on reaching a binding security agreement that will govern U.S.-Afghanistan relations after American troops leave. The U.S. plans to bring most forces home by 2015 and intends withdraw the 33,000 additional troops that President Barack Obama sent to Afghanistan in late 2009 by the end of the fighting season in 2012, 10,000 of them by the end of this year.

The U.S. hopes to have the security agreement ready before an international conference on Afghanistan’s future in early December. That will be meant as a signal to Afghanistan and the region that the U.S. will remain engaged and involved, according to the U.S. official.