WASHINGTON (AFP) -  The United States on Tuesday denied its drone strikes in Yemen and Pakistan and elsewhere infringed international law and said it did all it could to avoid civilian casualties.
The comments followed the publication of reports on the US drone war by two human rights groups, and came a day before Pakistani Prime Minister Nawaz Sharif is expected to bring up concerns about the US tactic at White House talks.
"We are reviewing these reports carefully," White House spokesman Jay Carney said.
"To the extent these reports claim that the US has acted contrary to international law , we would strongly disagree.
"The administration has repeatedly emphasised the extraordinary care that we take to make sure counterterrorism actions are in accordance with all applicable law ."
Carney also said that by deciding to use drone aircraft against terror suspects, rather than sending in troops or using other weapons, Washington was "choosing the course of action least likely to result in the loss of innocent life."
Earlier Amnesty International and Human Rights Watch unveiled reports detailing civilian casualties in a number of US operations in Pakistan and Yemen.
Human Rights Watch and Amnesty International are jointly calling on the US Congress to fully investigate the cases the two organisations have documented as well as other potentially unlawful strikes, and to disclose any evidence of human rights violations to the public. Those responsible for unlawful killings should be appropriately disciplined or prosecuted.
The groups called on Obama to provide a full legal rationale for targeted killings in Yemen and elsewhere.
With Pakistan Prime Minister Nawaz Sharif set to visit the White House on Wednesday (today), US President Obama is hoping to make progress on rebuilding an unsteady relationship between the two countries, according to American officials.
“The Prime Minister's official visit comes as we are strengthening US-Pakistan relations ," White House Press Secretary Jay Carney said at his media briefing on the eve of the important talks.
"We want to advance our shared interest of a stable, secure, and prosperous Pakistan that is contributing to regional and international security and prosperity," Carney said. "We want to find ways for our countries to cooperate, even as we have differences on some issues, and we want to make sure that the trajectory of this relationship is a positive one."
He described US-Pakistan relationship as "a very important" one that obviously has "got a lot of complexity to it, but it's enormously valuable when it comes to US national security and to the safety and security of the American people."
Earlier, prior to his meeting with Nawaz Sharif, US Secretary of State John Kerry said the relationship with Pakistan "could not be more important.''
Continuing his emphasis on the importance of the relationship, Carney said:
“It’s obviously a very important relationship -- the United States and Pakistan .  It’s one that’s obviously got a lot of complexity to it, but it’s enormously valuable when it comes to US national security and to the safety and security of the American people.”
Ahead of Nawaz Sharif's visit, Washington decided to release more than $1.6 billion in military and economic aid to Pakistan . The aid was suspended after relations hit a low following the US raid in 2011 in which al-Qaeda leader Osama bin Laden was killed in his compound in Pakistan . Relations also have been deeply affected by other issues such as the US drone strikes against suspected militants.
One area where Prime Minister Nawaz Sharif is unlikely to win US support is Pakistan 's decades-long dispute with neighbouring India over Kashmir. Before reaching Washington, Sharif said in London that US intervention would help resolve the Kashmir issue between India and Pakistan .
The United States, as part of its effort to maintain close relations with India, has refused to get involved in the Kashmir dispute, maintaining it is a bilateral issue which India and Pakistan must settle on their own.
On Sunday, as the Pakistani leader arrived, US officials refused to endorse Nawaz Sharif's call for internationalising the Kashmir dispute and instead urged him to stay engaged with India for resolving the issue.
One US official went on to say: "On Kashmir, our policy has not changed an iota."
While reviewing Nawaz Sharif's meeting with Obama, senior US administration officials said - also on Sunday - the United States and Pakistan would continue to discuss the drone strikes in Pakistan 's Tribal Areas but only as part of a larger security issue.
Meanwhile, Amnesty International said Monday in a report released just a day before the Sharif-Obama meeting US that drone attacks in Pakistan have killed at least 29 noncombatants since 2012 – deaths that could be categorised as war crimes.
Diplomats noted that the timing of the report's release puts perhaps the most sensitive issue in US-Pakistan relations in the spotlight as the two leaders meet.
President Obama publicly acknowledged a drone programme in Pakistan in January 2012, and promised greater transparency in May 2013.
US Officials also said the Obama-Nawaz meeting would focus on bilateral relationship, including energy, economy, terrorism and extremism.
In an open letter to President Obama, Shuja Nawaz, who heads the South Asian Center at Washington’s Atlantic Council, an American think-tank – underscored Nawaz Sharif's record and urged the US leader to trust him as "he represents a chance to provide continuity for civilian governance in Pakistan and to build a relationship that goes beyond our immediate need to exit Afghanistan gracefully."
But Farahnaz Ispahani, who served as an aide to former President Asif Ali Zardari, had a different perpective. "I feel this is a temporary feel-good moment," Ms Ispahani was quoted as saying in USA Today.