A top US military commander has warned the Pakistan army that America could launch ground operations in the tribal areas, if Islamabad refused to dismantle the militant network in North Waziristan.
The New York Times (NYT) reports the warning by General David H Petraeus, the Commander of US and NATO forces in Afghanistan, indicates US officials' belief that the Pakistanis are unlikely to launch a military operations in North Waziristan, which is considered to be a haven for al-Qaeda and Taliban operatives.
"Petraeus wants to turn up the heat on the safe havens," a senior official was quoted as saying, and this was the reason that US forces had sharply stepped up drone strikes in the area.
"He has pointed out to the Pakistanis that they could do more," NYT reports.
The official said that the drone operations had also been intensified to pre-empt a possible terrorist attack in several European countries. US and European intelligence agencies are evaluating the intelligence data of a possible al-Qaeda or Taliban attack on the European mainland.
As part of its covert war in the region, the CIA has launched 20 drone attacks in the last 24 days, killing more than 100 Taliban and foreign militants. The strikes have been mainly targeted to hit the Haqqani network, which the Americans believed is based in the area.
"There are some pretty notable threat streams," one US military official, was quoted as saying by The Wall Street Journal.
Beyond the CIA drone strikes, the war in the region is escalating in other ways. American military gunships have launched three strikes into Pakistan that military officials estimate killed more than 50 people suspected of being members of the Haqqani network, which is responsible for the spate of deadly attacks against American troops.
Such air strikes by the US and NATO military forces remain rare, the US special representative for Afghanistan and Pakistan Richard Holbrooke has defended them saying that Western Pakistan is becoming one of the most dangerous parts of the world.
The NYT said the strikes point to a new willingness by military officials to expand the boundaries of the campaign against the Taliban and Haqqani network, while American "surge" forces are in Afghanistan.
Pakistani officials have angrily criticised the helicopter attacks saying that NATO's mandate in Afghanistan does not extend across the border into Pakistan.
The NYT said that special operations Commanders have also been updating plans for cross-border raids, which would require approval from President Obama.
For now, official said it remains unlikely that US would make good on such threats to send America troops over the border, given the blowback inside Pakistan, an ally.
But, the NYT said that could change, if Pakistan based militants were successful in carrying out terrorists attacks on American soil.