Pakistan's army chief has cancelled a planned visit to Britain amid escalating tensions between Islamabad and the United States over security.
Britain's defence ministry said General Ashfaq Kayani had been due to meet UK defence minister Liam Fox for a private meeting in London on Monday.
The ministry declined to speculate on why the visit was cancelled.
Kayani was also scheduled to address the International Institute for Strategic Studies and the Royal College of Defence Studies.
A Pakistani official said Kayani was staying in Pakistan to hold talks on a crisis sparked by US accusations against Pakistan's military-run Inter-Services Intelligence spy agency, according to the AP news agency.
The official spoke on condition of anonymity because of the sensitivity of the situation.
Kayani met his army commanders in the capital, Islamabad, on Sunday, days after Admiral Mike Mullen, the chief of the US military, accused Pakistan's spy agency of backing the Haqqani group.
Washington blames the group for the recent attack on its embassy and other targets in Kabul, the Afghan capital.
Without giving further details on Sunday's meeting, Major-General Athar Abbas, the Pakistani army spokesman, said: "The prevailing security situation was discussed."
Separately on Sunday, General James N Mattis, the US central command (CENTCOM) commander, met Khalid Shameem Wynne, chairman of Pakistan's Joint Chiefs of Staff Committee, who expressed concern over the "negative statements emanating from [the] US".
The US and Pakistan have been in a war of words over alliances
"He [Wynne] stressed upon addressing the irritants in relationship which are a result of an extremely complex situation," the military said in a statement.
"He reiterated that Pakistan armed forces are committed to achieving enduring peace in the region which will only be possible through mutual trust and co-operation."
In the most blunt remarks by a US official since Pakistan joined the US-led war on terror in 2001, Mullen, the outgoing chairman of the joint chiefs of staff, testified before the US Senate that the Haqqani network was a "veritable arm" of the Inter Services Intelligence (ISI).
He also for the first time held Islamabad responsible for the Kabul attack, saying Pakistan provided support for that assault.
Shaukat Qadir, a retired Pakistani brigadier, said the US was having difficulty defeating terror networks.
"The fact is the US in Afghanistan is failing. I think that fact is pretty obvious to everybody. The Taliban shouldn't be gaining ground everyday," he told Al Jazeera.
"And the all-mighty, all-powerful US cannot fail against a ragtag force of the Taliban for God's sake. So there has to be something behind that."
The Pakistani government and its army rejected Mullen's charges and Yousuf Raza Gilani, the prime minister, spoke to political leaders by telephone on Sunday and decided to call a meeting to discuss the issue of tensions with the US.
On Saturday night, Gilani rejected the allegations as a sign of US "confusion and policy disarray".
Relations between the US and Pakistan have been strained since the US forces' killing of al-Qaeda leader Osama bin Laden on Pakistani soil in an unannounced raid in May.
Abbas acknowledged that army's directorate of the ISI maintained contacts with the Haqqani network, but said that did not mean it backed it.
"No intelligence agency can afford to shut the last door of contact," he told the Reuters news agency. "Maintaining contact doesn't mean that you are endorsing or supporting that terrorist organisation."
The Haqqani network is the most violent and effective faction among Afghanistan's Taliban fighters.
Although Pakistan officially withdrew support for the Taliban after the September 11 attacks on the United States in 2001 and allied itself with Washington's "war on terrorism", analysts say elements of the ISI refused to make the doctrinal shift.
A US senator said Washington would have to get tougher in confronting Pakistani support for terror networks.
"We need to put Pakistan on notice," Lindsey Graham, a Republican member of the Senate's armed services committee, said.
"If they continue to embrace terrorism as part of their national strategy we're going to have to put all options on the table, including defending our troops," he told Fox News.
Graham also said Washington needs to make billions of dollars in aid to Pakistan more conditional on co-operation.
Source: Al Jazeera and agencies