US intelligence reports said senior Pakistani military and intelligence officials knew of and possibly ordered a broad campaign of extrajudicial killings of militants and other adversaries, The Washington Post reported on Tuesday, adding that public disclosure of such information could have forced the Obama administration to sever aid to the Pakistani armed forces on account of a US law that prohibits military assistance to human rights abusers.

These reports are based on communications intercepts from 2010 to 2012 and other intelligence in classified documents provided to it by former National Security Agency contractor Edward Snowden.

The documents indicate that administration officials decided not to press the issue so as to preserve its relationship with Pakistan which was already frayed at the time.

The Post moreover reported that US spy agencies had also shifted their attention to what they classified as dangers surfacing outside Pakistani areas patrolled by CIA drones.

It reported that the US had intensified surveillance of Pakistan's nuclear weapons, has been concerned about biological and chemical arms sites there and has been trying to evaluate the loyalty of Pakistani counter-terrorism agents recruited by the CIA.

The paper was quoting from a 178-page summary of what it called the US intelligence community's “black budget” provided to it by Snowden.

“If the Americans are expanding their surveillance capabilities, it can only mean one thing,” said Husain Haqqani, who served as Pakistan's ambassador to the US from 2008 to 2011.

“The mistrust now exceeds the trust.”

America has delivered nearly $26 billion in aid to Pakistan over the past 12 years, with the money aimed at stabilising the country and ensuring its cooperation in counterterrorism efforts, the paper said.

However, as classified documents reveal new allegations of human rights abuses by the Pakistan army, a spokeswoman for the National Security Council seems to have played it down in the Post report saying the United States would “continue to work closely with Pakistan's professional and dedicated security forces” in order to combat the challenging security issues in Pakistan.

Spokeswoman Caitlin Hayden in a statement said the US is “committed to a long-term partnership with Pakistan, and we remain fully engaged in building a relationship that is based on mutual interests and mutual respect”.

“We have an ongoing strategic dialogue that addresses in a realistic fashion many of the key issues between us, from border management to counterterrorism, from nuclear security to promoting trade and investment,” Hayden said.

“The United States and Pakistan share a strategic interest in combating the challenging security issues in Pakistan, and we continue to work closely with Pakistan's professional and dedicated security forces to do so.”