The Pakistani Army on Tuesday identified him as Muhammad Ali Qasim Yaqub, alias Abu Sohaib Al-Makki, and said he had been "working directly under Al-Qaeda leaders along (the) Pakistan-Afghan border".

Makki's arrest was the first of what authorities said was a prominent militant since US special forces killed Osama Bin Laden on May 2 in a secret raid which angered the powerful Pakistani Army.

“He is a mid-level operative and has been very active in the region, but I can't say yet if he is 'huge' in the global scheme of things,” said the official, adding intelligence agencies arrested him about a week ago in central Karachi.

“Nonetheless, he is a very good catch.”

There was no immediate way of verifying Makki’s rank within Al- Qaeda.

Pakistan's reputation was badly hurt after it was discovered that Bin Laden was living in a compound in a garrison city about a two-hour drive from intelligence headquarters in the Islamabad.

The nuclear-armed country, which depends on billions of dollars in US aid, is now under intense pressure to capture or kill other senior Al-Qaeda figures to prove that it is serious about tackling militancy.

Al-Makki was among prisoners who escaped from a prison in the Afghan city of Kandahar in 2008, two Pakistani officials said.

Around 1,000 prisoners including insurgents escaped after a truck bomb blew open the jail's gates. The mass escape led to a surge in fighting in Afgahnistan.

Retired army general Talat Masood said Pakistan must boost cooperation with ally the United States in its fight against militancy given the embarrassment caused by Bin Laden's presence.

“I think it's too dangerous for Pakistani security agencies to create any drama (to hoodwink Americans) at this stage,” he said.

“It seems to me it was a genuine catch and they have to share it (information) with Americans, otherwise it will be meaningless,” he said.

A military official in Islamabad said Al-Makki was an “explosives expert.” The official said he was "definitely" linked to the Al-Qaeda leadership but did not elaborate.

“He is still being interrogated and we hope to get more information from him,” said the official.

A security official in Islamabad said Al-Makki was between 35 and 40 years old and had been living with his three children and wife “for some time.”

Military sources said that he came to Pakistan in 2001 and operated along Pakistan's border with Afghanistan.

“The whole Osama issue has been very embarrassing for us, and that is why we have significantly stepped up efforts to capture any militants that may be hiding here,” said another military official.

“We have always been very serious on terrorism, but now we are moving against militants even more seriously. You will hopefully see more results soon.”

Pakistani officials say militants generate funds through extortion and kidnapping in Karachi.

Al-Makki lived in Karachi for two years, said the intelligence officials. He speaks, English, Arabic and Pashtu. Arab militants inspired by Al-Qaeda are based in the tribal belt along the Pakistani-Afghan border.

“According to some documents we confiscated and, and also during the interrogation, he said he was trying to flee the country after Osama's (Bin Laden's) killing,” said one of the officials.

Army offensives have failed to break the resolve of Pakistani Taleban insurgents, who are close to Al- Qaeda.