The head of U.S. and NATO forces in Afghanistan is visiting Pakistan Wednesday to urge Pakistani officials to crack down on militants who launch cross-border attacks into Afghanistan.

U.S. General John Allen is holding talks with Pakistani army chief General Pervez Ashfaq Kayani.

The United States has repeatedly called on Pakistan to go after the Haqqani network.

The al-Qaida-linked militant group is based in Pakistan's North Waziristan tribal region and has carried out numerous attacks in Afghanistan.

Last week, at least 20 people were killed in a militant siege of a lakeside hotel outside the Afghan capital, Kabul.

General Allen said the attack bore the signature of the Haqqani network. He said the group continues to target and kill innocent Afghans and violate Afghan sovereignty from, in his words, “the safety of Pakistan.”

Pakistan's military says the NATO commander and Pakistani army chief are discussing the implementation of “recently evolved” border coordination measures.

General Allen's visit to Pakistan comes amid heightened tensions between the United States and Pakistan over the still-closed NATO supply routes into Afghanistan.

Islamabad shut down the supply lines after last November's coalition airstrikes that mistakenly killed 24 Pakistani troops along the border.