Updated

Congressional aides say senators have dropped a demand that the U.S. publicly declare how many civilians it kills in drone strikes.

The provision was in Congress' main intelligence bill for 2014, which hasn't yet been adopted. It would have directed President Barack Obama's administration to give combatant and noncombatant death tallies from drones for the year.

Aides say the requirement was dropped after the administration objected.

U.S. intelligence chief James Clapper sent a letter to the Senate Intelligence Committee this month warning against disclosing sources and classified information. He said the administration was exploring ways to provide greater information.

Obama tightened rules for drone attacks last year, partly to limit unintended casualties.

Rights groups say the U.S. has killed hundreds of civilians in Pakistan and Yemen, though deaths have declined.