Washington, Nov 4 : The Central Intelligence Agency (CIA) has made a series of secret concessions in its drone campaign after military and diplomatic officials complained large strikes were damaging the already soured relationship between the US and Pakistan.

The covert drones are credited with killing hundreds of suspected militants, and few U. S. officials have publicly criticized the campaign, or its rapid expansion under President Barack Obama. Behind the scenes, however, many key U. S. military and State Department officials demanded more-selective strikes, The Wall Street Journal reports.

The disputes over drones became so problematic that the White House launched a review over the summer, in which Obama intervened.

The review ultimately affirmed support for the underlying CIA program. But a senior official said: "The bar has been raised. Inside CIA, there is a recognition you need to be damn sure it''s worth it."

Among the changes: The State Department won greater sway in strike decisions, Pakistani leaders got advance notice about more operations, and the CIA agreed to suspend operations when Pakistani officials visit the US, the paper said.

The Pakistan drone debate already seems to be influencing thinking about the U. S. use of drones elsewhere in the world.

In Yemen, the CIA used the pilotless aircraft in September to kill American-born cleric Anwar al-Awlaki, a suspected terrorist. But the White House has for now barred the CIA from attacking large groups of unidentified lower-level militants there, the paper added. (ANI)