Last year, during the chaotic US withdrawal from Afghanistan, President Joe Biden pledged his administration would not allow the new Taliban-led regime to make the country a safe-haven for terrorists.

The remarks were intended to indicate that, as far as Mr Biden's White House was concerned, the decades-old war on terror was far from over. Almost a year later, the president's top security advisers approached him and suggested that intelligence officials may have located the leader of al-Qaeda, Ayman al-Zawahiri, in Afghanistan.

Identifying a high-value target In background briefings, senior administration figures told reporters that they believed Zawahiri had returned to Afghanistan in the past year, following the collapse of the Western-backed government. US spies had been carefully watching Afghanistan ever since the US withdrawal for signs that al-Qaeda leaders were slowly filtering back into the country, an adviser to Mr Biden said.

Zawahiri is said to have settled in a large compound with high, protective walls, in downtown Kabul with his wife and daughter. Online Job in USA from Bangladesh. Salaries Might Surprise You! Online Jobs In USA l Search AdAd The neighbourhood Zawahiri chose, a relatively well-to-do area called Sherpour, was home to foreign embassies and diplomats under the previous administration. Now, most of the Taliban's senior officials live in its plush surroundings. In early April, CIA officers first briefed Mr Biden's advisers, and then the president himself, informing him that they had identified a network supporting the al-Qaeda leader and his family through multiple streams of intelligence, according to the briefings. The spies had slowly established patterns of behaviour from the house's residents, including the unique mannerisms of a woman that spies identified as Zawahiri's wife.

Officials said they had recognised her use of terrorist "tradecraft", which she used in an attempt to avoid leading anyone to her husband's safehouse in Kabul. They observed that after arriving at the house, Zawahiri never personally left the premises. But they did note his habit of appearing periodically on a balcony overlooking the property's walls for short periods of time.