NEW YORK - The United States believes it has Pakistan's 'tacit consent' for drone strikes within its sovereign territory, The Wall Street Journal reported Wednesday, citing officials familiar with CIA programme.The CIA informs Pakistan in advance about "broad areas" where it intends to take aim at suspected terrorists with drone strikes and interprets Islamabad's silence and clearing of airspace as "tacit consent," the newspaper said in a front-page dispatch.Citing "US officials" and "two senior [Obama] administration officials," the Journal adds, "The rationale used by the administration, interpreting Pakistan's acquiescence as a green light, has set off alarms among some administration legal officials. In particular, lawyers at the State Department, including top legal adviser Harold Koh, believe this rationale veers near the edge of what can be considered permission, though they still think the programme is legal, officials say." Officially, says the Journal, "representatives of the White House's National Security Council and CIA declined to discuss Pakistani consent, stating such information is classified." The strikes are aimed at fighters from al-Qaeda, the Taliban and other groups that use parts of Pakistan as a safe haven from which to launch attacks in neighbouring Afghanistan. Two senior administration officials, according to WSJ, described the approach as interpreting Pakistan's silence as a "yes." One dubbed the US approach "cowboy behaviour.""In a reflection of the programme's long-term legal uncertainty and precedent-setting nature, a group of lawyers in the administration known as "the council of counsels" is trying to develop a more sustainable framework for how governments should use such weapons," the dispatch said.Drone strikes in Pakistan have been fewer since David Petraeus took over the CIA, the newspaper claimed. It said that by carrying out drone strikes, the White House is also worried about setting precedents for other countries, including Russia or China, that might conduct targeted killings as such weapons proliferate in the future. Because there is little precedent for the classified US drone programme, international law doesn't speak directly to how it might operate. That makes the question of securing consent all the more critical, legal specialists say.In public, WSJ noted, Pakistan has repeatedly expressed opposition to the drone programme, and about 10 months ago closed the CIA's only drone base in the country. In private, some Pakistani officials say they don't consider their actions equivalent to providing consent, according to the paper. They say Pakistan has considered shooting down a drone to reassert control over the country's airspace but shelved the idea as needlessly provocative. Pakistan also has considered challenging the legality of the programme at the United Nations."No country and no people have suffered more in the epic struggle against terrorism than Pakistan," Pakistan President Asif Ali Zardari told the UN General Assembly on Tuesday. "Drone strikes and civilian casualties on our territory add to the complexity of our battle for hearts and minds through this epic struggle." A former Pakistani official who remains close to the programme said Pakistan believes the CIA continues to send notifications for the sole purpose of giving it legal cover, according to WSJ.Legal experts say US law gives the government broad latitude to pursue al Qaeda and its affiliates wherever they may be.Government consent provides the firmest legal footing, legal experts say. The US has that in Yemen, whose government assists with US strikes against an al Qaeda affiliate. In Somalia, the nominal government, which controls little territory, has welcomed US military strikes against militants.In an April speech, White House counterterrorism adviser John Brennan said the administration has concluded there is nothing in international law barring the US from using lethal force against a threat to the US, despite the absence of a declared war, provided the country involved consents or is unable or unwilling to take action against the threat.Meanwhile, a report from human rights researchers at the Stanford and New York University law schools state that the drone strikes in recent years have killed and injured many more Pakistani civilians - possibly close to 900 - than the US has acknowledged.The New York Times AtWar blog states that the report also concludes that the strikes have "alienated Pakistani public opinion and set a dangerous precedent under international law."United Nations experts say the drone strikes may violate international law.