Islamabad , Pakistan ( CNN ) -- Pakistan has issued a strongly-worded statement condemning a deadly , suspected U.S. drone strike in the country 's tribal region . `` Drone attacks have become a core irritant in the counter-terror campaign , '' a statement from the Ministry of Foreign Affairs said Wednesday . `` We have repeatedly said that such attacks are counter productive and only contribute to strengthen the hands of the terrorists . '' Pakistan 's Foreign Secretary has lodged a strong protest with the U.S . Ambassador , according to the statement , and the government has `` taken up the matter with the U.S. at all levels . '' Six suspected militants were killed Wednesday when a suspected drone fired two missiles at a hideout in South Waziristan , Pakistani intelligence officials told CNN . The officials asked not to be named because they are not authorized to speak to the media . Drone strikes are now carried out autonomously by the CIA , a senior Pakistani intelligence official told CNN earlier . `` It 's unilateral action , '' he said as he expressed dismay at Wednesday 's strike . The U.S. does not officially acknowledge the Central Intelligence Agency 's secret drone program in Pakistan , but it is the only country operating in the region with the capacity to carry out such strikes . It was once widely believed that the program had the tacit approval and cooperation of Pakistan 's intelligence agency . Pakistani intelligence officials say Islamabad has asked the U.S. to curtail its drone strikes in remote tribal areas . `` We are not necessarily saying stop . What we are saying is irrespective of tactical games , this is not useful in the long run , '' one source told CNN . `` We need a relook and to not be too trigger happy and be selective . '' Wednesday 's strike is the first since March 17 , when a drone strike in North Waziristan killed 44 people -- most of them civilians , two Pakistani sources said . It 's the 19th strike this year , according to a count by CNN 's Islamabad bureau . Such strikes have inflamed tensions between Pakistan and the United States . Pakistan has formally asked the United States for an apology . On Monday , Pakistan 's intelligence chief , Lt. Gen. Ahmed Shuja Pasha , met with CIA Director Leon Panetta at CIA headquarters to voice his government 's complaints about CIA activities in his country . U.S.-Pakistani relations have been strained for some time because of ongoing American intelligence operations within Pakistan 's borders . Tensions came to a head recently when when CIA contractor Raymond Davis was arrested after killing two Pakistani men in Lahore . Although the United States said Davis was a security officer assigned to protect CIA officers , the Pakistanis maintained he was actually a spy whom they had been unaware of prior to the shooting incident . Pakistani officials insisted this week that the United States give them details about other CIA contractors in the country .
Pakistan calls U.S. drone strikes `` counter productive '' A drone fired 2 missiles at a suspected militant hideout , officials say . Official : The strike was in the North Waziristan tribal area of northwest Pakistan. Tensions between Pakistan and U.S. have been rising in recent months .