The Site Intelligence Group, which tracks social media postings by Islamist groups, translated a series of messages by AQAP sympathisers that al-Wuhayshi had died. AQAP is considered the terror group most capable of striking US interests. Al-Wuhayshi joined al-Qaeda 1998 and became head of AQAP in 2009.
Meanwhile, three British sisters - Khadija Dawood, 30, Sugra Dawood, 34, and Zohra Dawood, 33, - are feared to have gone to Syria with their nine children, one as young as 3, to join their brother fighting there.
The family, from Bradford, disappeared after first going to Saudi Arabia on an Islamic pilgrimage but are believed to have then flown to Turkey and have not been heard of in a week. Their distraught husbands fear the children's lives are now in danger. Police also faced questions after reports the sisters were under watch prior to vanishing. Balaal Khan, a lawyer acting for the husbands, said police were notified five or six days ago but were limited in what they could do. However, a family friend claimed the sisters had been under "extensive police surveillance", according to Channel 4 News.
It came as police chiefs and senior politicians warned how easily people were being fooled by Isis (Islamic State). It is feared "charismatic recruiters" are "brainwashing" people online as community leaders urge parents and public to help root out the groomers.
The growing influence of terror groups in attracting youngsters to their campaign has caused alarm among security services and government in a series of new developments. Talha Asmal, 17, was this week named as Britain's youngest suicide bomber after blowing himself up for Isis in an attack on Iraqi forces. The typical age range for Britons joining jihad has fallen from around 25 to 35, during the Afghanistan war, to 14 to 26 now. For the first time, significant numbers of Muslim women and girls in the West are joining the conflict.
In Syria, Isis was routed from one of its key strongholds on the border with Turkey after its defences crumbled and its fighters defected or fled, raising questions about its vaunted military capabilities.
The fall of Tal Abyad to a Kurdish-Syrian rebel force backed by US airstrikes came after just two days of fighting, during which the militants appeared to put up little resistance, focusing instead on escaping to Raqqa or Turkey.
The force, led by Kurdish members of the People's Protection Units, or YPG, and including local battalions of the rebel Free Syrian Army, pulled down the Isis flag from the border crossing with Turkey and claimed they were in control of the town centre. There were reports of scattered fighting on the western outskirts of Tal Abyad, but the advancing force had already severed the militants' escape route, closing in on the town in a pincer movement from the east, south and west.
Photographs posted on social media by local activists showed groups of Isis fighters surrendering to Turkish forces and being led away after fleeing across the border. Syrians who had fought with Isis were among more than 10,000 refugees who scrambled across the border to the Turkish town of Akcakale on the opposite side of Tal Abyad in recent days, according to a Syrian aid worker.
- Telegraph Group Ltd, Washington Post-Bloomberg, AP