The growing instability in Pakistan and Afghanistan tops the agenda when U.S. President Barack Obama meets with Afghan President Hamid Karzai and Pakistani President Asif Zardari this week in Washington. The regional talks were initially expected to focus on countering the Taliban in Afghanistan, but recent turmoil in Pakistan has generated concern that Islamabad's problems are more serious.

Last week Pakistani security forces directly confronted Taliban militants in mountainous areas just 100 kilometers from the capital. Airstrikes and artillery barrages effectively ended months of negotiations to try to avoid violence by establishing Islamic law in parts of the northwest.

Professor Pervez Hoodbhoy of Islamabad's Quaid-e-Azam University says the  Talibans rapid advance towards the capital was a wake-up call for the government.

"The fact is the situation is grim," Hoodbhoy said.  "The fact is that the Taliban have made enormous inroads into the country. And it's not just that they are in FATA, the tribal areas. They are in our cities and that is even more dangerous."

Pakistan has battled Taliban militants in its northwest tribal areas since the U.S.-led invasion of Afghanistan, but the fighting is now moving closer to population centers, forcing tens of thousands of civilians to flee.

Professor Hoodbhoy says the government for years tried to ignore or minimize the spreading influence of the militants, without acknowledging that the situation continued to worsen.

"The present situation is where religious extremists - whether they be the Taliban or whether they be one of the very many other jihaidst groups that were early on nurtured by the Pakistan army - they are pretty much beyond control now," Hoodbhoy said. 

Government attempts to strike peace deals with the militants have not stopped the fighting and have sparked criticism from U.S. officials. But the failure of the talks has also hurt the Taliban's image among the Pakistani public.

Military analyst Talat Masood says militant leaders' denunciation of government and religious leaders as un-Islamic, hardened Pakistani attitudes against the Taliban.

"They do not want the present administration to function," Masood said. "They want a Pakistan of their own vision. Which completely undermines the Pakistani state. I think the people are seeing it and that is where a good thing is happening."

Pakistan's new offensive against Taliban militants has been praised by U.S. officials eager for a more aggressive approach. But the army's limited capacity for counterinsurgency operations and a weak central government have many concerned that the situation could worsen.

Relations between Pakistan and the U.S. government remain tense. U.S. drone strikes against suspected militants in the tribal areas are unpopular - especially when they kill civilians.

Masood says there are still tensions with Afghanistan, which many Pakistanis blame for their own worsening security.

"There will be other concerns as well in regards to the stability of Afghanistan," Masood said. "How it is impacting Pakistan and especially in the areas of drug trafficking, in the areas of corruption that exist in Afghanistan which have given power to a lot of warlords which make Afghanistan in a state of perpetual instability."

The last time the leaders of the three countries met, in 2006, their summit in Washington was overshadowed by bickering over who was to blame for the Taliban's growing strength.  Two years and two leaders later, the tensions remain and the Taliban control more territory in both countries.