Islamabad, Pakistan (CNN) -- In Pakistan to repair damaged relations, CIA Director Leon Panetta urged top officials to step up efforts to hunt militants operating within its borders as the United States reduced troop levels in the south Asian nation at the request of Islamabad.
Between 200 and 300 U.S. military personnel remain in Pakistan, said a U.S. military spokesman, who asked not to be identified. It's not known what the previous number was but an official U.S. statement said the reduction was in line with a request from the Pakistani government.
"We recently received a written request from the Government of Pakistan to reduce the number of U.S. military personnel here, and we have nearly completed that reduction," said Navy Vice Adm. Michael LeFever, a U.S. defense representative in Pakistan.
Pakistan's military chief Gen. Ashfaq Parvez Kayani said the United States "has drastically cut down" troop strength in Pakistan.
Panetta met with the chiefs of Pakistan's military and top spy agency Friday to discuss U.S. partnership with Pakistan, strained by disputes about how to pursue counter-terrorism efforts.
Panetta's unannounced visit was the latest in a series of such visits by U.S. officials -- among them, Secretary of State Hillary Clinton, Chairman of the Joint Chiefs of Staff Adm. Mike Mullen and Sen. John Kerry -- in efforts to smooth things over after Osama bin Laden was killed in a Navy SEALs raid in early May.
Panetta insisted that Pakistan launch a military operation in North Waziristan, a rugged mountainous region rife with militants, according to a senior Pakistani official who asked to remain anonymous because he is not authorized to speak to the media.
Kayani agreed with Panetta in principle but told the incoming defense secretary that Pakistani troops are already stretched thin.
Panetta and his Pakistani counterparts agreed to form a joint intelligence team to track militant targets inside Pakistan.
U.S. officials believe Pakistan is not doing enough to go after al Qaeda and other extremists, while the Pakistanis are upset with what they consider to be unilateral steps taken by the United States within their borders.
Washington did not give advance notice to Pakistani officials about the raid on bin Laden's compound in Abbottabad.
At his confirmation hearing Thursday for defense secretary, Panetta, described the U.S. relationship with Pakistan as "difficult" but "critical."
While Pakistan has proven to be a safe haven for extremists, a positive relationship with authorities in Islamabad is vital to the mission in Afghanistan, he said.
CNN's Pam Benson and Phil Black and journalist Nasir Habib contributed to this report.