The relationship between the United States and Pakistan has seen a "significant improvement" under the Obama administration, the U.S. special envoy to Afghanistan and Pakistan said Sunday, attributing recent Taliban arrests to increased communication between the two governments.

"No government on earth has received more high level attention," Ambassador Richard Holbrooke told CNN's "Fareed Zakaria GPS" of the dozens of visits by top U.S. officials to their counterparts in Pakistan.

"All of this, plus the recognition that the distinction between Afghan Taliban and Pakistan Taliban - if it ever existed - is eroded, has led the Pakistanis to take a very much more forward leaning position," Holbrooke said. "Plus, above all, the backlash from the (Taliban's) attacks in places like Lahore or Rawalpindi, Islamabad, Kashmir, Karachi, have all contributed to an evolution."

Holbrooke cited the arrest of the Taliban's No. 2 official, Mullah Abdul Ghani Baradar, as evidence of Pakistan's evolution from a country on the verge of collapse to a more stable political system now.

Baradar is one of at least six Taliban leaders to be arrested in the past month, according to Pakistani officials. Some analysts say the arrests underscore a change in Pakistan's policy brought on by pressure from the United States for higher levels of cooperation.

Speaking about the NATO-led fight against the Taliban in Afghanistan, Holbrooke also cited an improved relationship with Afghan President Hamid Karzai, who endorsed a massive military offensive - dubbed Operation Moshtarak – last month in Marjah in southern Helmand province against the Taliban insurgency.

The top U.S. commander in Afghanistan, Gen. Stanley McChrystal, has said Afghan and international forces will continue counterinsurgency operations in the coming months in the volatile Kandahar province, where a series of explosions Saturday killed at least 35 people in what the Taliban called a "message" to McChrystal.

Holbrooke saved his harshest words for al Qaeda when asked about the state of the terrorist organization now. Holbrooke said the leadership is under "fantastic pressure" since losing about half of its top 20 people in the past year.

"It looks like they are less an organization that plans operations now than an organization that summons people to aspirational jihad," he said, adding that brutal tactics by the group may be alienating its followers.

"Their excessive brutality, the backlash against things - like the bombing of the wedding in Jordan, the beheading of people, the videotape in Swat of the flogging of the young girl - have created a revulsion against them," he said. "It's pure nihilism. They stand for absolutely nothing except destruction, and they destroy people's lives in a random and insane way."