The announcement that Mullah Abdul Ghani Baradar, the Afghanistan Taliban's military chief, was arrested underscores increasing US-Pakistan intelligence cooperation, targeting Taliban leaders inside Pakistan for arrest and assassination.

The Afghanistan Taliban's chief military commander was captured in a joint operation between Pakistani and American spy agencies near Karachi.

Agents from the two countries nabbed Mullah Abdul Ghani Baradar in the Pakistani commercial capital of Karachi 10 days ago. News of his arrest broke Monday night. Mr. Baradar is said to be the Taliban's No. 2, working underneath Mullah Omar as the organization's top military commander for southern Afghanistan

In the past, Pakistan has rarely targeted Afghan Taliban leaders operating within its borders. Instead, Islamabad has focused on shutting down the Tehrik-i Taliban Pakistan (TTP), a faction that is at war with the Pakistani government.

But US-Pakistan relations have improved of late, with Pakistan feeding intelligence to the US drone assassination program operating inside the country and the US helping Pakistan kill its enemies in return.

A US drone strike in August smote Pakistan's chief enemy, former TTP chief Baitullah Mehsud. The arrest of Baradar appears to be reciprocal -- a sort of reward to the US for its help in killing Mr. Mehsud.

"There is more intelligence sharing now than at any point in time in the last seven or eight years," says Rifaat Hussain, chairman of the department of defense and strategic studies at the Quaid-i-Azam University in Islamabad. "After Baitullah Mehsud's killing it became quite clear that the Americans were willing to hit the TTP targets. Now the expectation was that the Afghan Taliban would be next."

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