Pakistan's prime minister Thursday signaled his country's cautious response to President Barack Obama's new policy for Pakistan and Afghanistan by declining to endorse the U.S.-led troop surge.

Instead, Prime Minister Yousuf Raza Gilani said his government needs more information about Obama's plan to expand the U.S. military presence in Afghanistan and at the same time increase aid to Pakistan.

Gilani said Pakistan was looking into the policy announced by Obama on Tuesday, including the suggestion that more covert CIA resources would be deployed in Pakistan, where the central government faces a strong threat from Islamic extremists.

"Regarding the new policy of President Obama, we are studying that policy," Gilani said during a joint news conference with his British counterpart Gordon Brown in London. "We need more clarity on it, and when we get more clarity on it, we can see what we can implement on that plan."

Unlike Brown, who strongly supports Obama's approach and is sending 500 more British troops to Afghanistan to augment the surge, Pakistani leaders remained silent until Gilani's carefully worded comments.

Analysts said the lack of a public endorsement of U.S. policy is in part a response to rising anti-American sentiment in Pakistan that prevents national leaders from publicly embracing expanded U.S. aid _ even if they need the support.

Since 2001, the U.S. has given the Pakistani army billions of dollars to try to get it to fight Islamic militants along the Afghan border. Starting last year, the U.S. began a sustained program of covert missile strikes against militant targets close to the border.

The results have been mixed. While the army has taken on the Pakistani Taliban, it has failed to go after Afghan Taliban leaders who base their operations in the tribal areas in the border region. At the same time, anti-Western sentiment, spurred by the security forces, has grown.

Many Western officials and analysts believe Pakistan is playing off both sides _ accepting U.S. funds to crack down on Pakistani militants while tolerating the Afghan Taliban in the expectation that the radical Islamic movement will take power in Afghanistan once the Americans withdraw.

Shaun Gregory, an expert on Pakistani security at the University of Bradford in Britain, said the Pakistanis will take note of Obama's pledge to start bringing U.S. troops home from Afghanistan in July 2011.

"The Pakistanis are smart enough to read the signals coming out of Washington," Gregory said. "It seems to me that the army's longer-term strategy of broadly backing the Afghan Taliban is paying off now. They have their tails up."