WASHINGTON - US Secretary of State Hillary Clinton said on Tuesday that Pakistan has informed Washington that it is reopening the ground supply routes for NATO forces in Afghanistan, which were closed after a deadly NATO airstrike on Pakistani border outposts last November.

"I'm pleased that (Pakistani) Foreign Minister (Rabbani) Khar has informed me that the ground supply lines into Afghanistan are opening," Clinton said in a statement after having a phone conversation with her Pakistani counterpart on Tuesday morning.

The two discussed over the phone the tragic incident of last November in Salala, near the Pakistan-Afghanistan border, in which 24 Pakistani soldiers were killed in the NATO airstrike.

"We are sorry for the losses suffered by the Pakistani military. We are committed to working closely with Pakistan and Afghanistan to prevent this from ever happening again," Clinton said in the statement, adding that she has "offered our sincere condolences" to the families of the killed Pakistani soldiers.

Clinton said she and Khar talked about the importance of taking coordinated action against terrorists, supporting Afghanistan's security, stability and efforts toward reconciliation, as well as continuing to advance shared interests between the United States and Pakistan.

The top US diplomat praised Pakistan for "a tangible demonstration" of its support for a secure, peaceful and prosperous Afghanistan by promising not to charge any transit fee for the use of the supply routes by the US-led NATO forces in Afghanistan.

"In concluding the call, I reiterated our deep appreciation to the government and people of Pakistan for their many sacrifices and their critical contribution to the ongoing fight against terrorism and extremism," Clinton said.

The NATO airstrike on the Pakistani outposts led to heightened tensions in the relations between Pakistan and the United States, as Islamabad closed all land supply routes to NATO forces in Afghanistan in retaliation. Pakistan also demanded a formal apology from the US government, which has so far been rejected by Washington.