Bradford (above) is a city in west Yorkshire, northern England. It is located about 14 km west of Leeds. Known as the curry capitol of Britain, Bradford has about 25% Muslim people mainly from Bangladesh, Pakistan, and India.
Three Bradford sisters and their nine children split into two groups to cross the border into Syria, an IS smuggler has told the BBC.
The smuggler in charge of some of IS's border operations said the first group went early on Wednesday and the second on Thursday.
Sisters Khadija, Sugra and Zohra Dawood and their children went missing after travelling to Saudi Arabia.
On Tuesday, two of their husbands made an emotional appeal for them to return. Akhtar Iqbal and Mohammed Shoaib said they "could not live" without their families and begged them to come home.
|The Sugra family|
"If what he says is true, it clears up the main ambiguity of this story - whether the sisters were really heading for the so-called Islamic State, or some other part of Syria, controlled by some other armed group," said our correspondent.
He said the information came up during a casual conversation with the smuggler, who is known to be an IS member, but when asked for an interview about the incident he asked for money which the BBC refused.
The information also fits with the news that one of the sisters, Zohra, sent a message to her family that she was inside Syria - but she did not say exactly where.
The North East Counter Terrorism Unit said it was "continuing to make extensive enquiries" in order to try and bring the women and children home.
|The Zohra family|
By Paul Wood, BBC Middle East correspondent
Every armed group in Syria has its own network of smugglers - and the so-called Islamic State is no different.
They move people - and sometimes cash and weapons - across the border for profit and for the cause.
Like all smugglers, IS uses a network of safe houses along the border, though the area of border open to them has been shrinking as they lose territory to a Kurdish military advance, backed by US airstrikes.
The Turkish security forces occasionally shoot, and kill, people crossing the border illegally, but most crossings are uneventful with many smugglers coming to "an arrangement" with the Turkish border guards.
|The Khadiya family|
Once inside Islamic State territory, however, the women and their children will not be allowed to leave.
I spoke to an activist who runs a secret network trying to get disenchanted jihadis out of the so-called caliphate.
He told me some 400 had been killed trying to leave - and that 200 women were under house arrest.
The group went missing following a religious pilgrimage to Saudi Arabia.
|Mohammed Shoaib (right) appeared in tears at the press conference alongside |
Akhtar Iqbal (centre) and family lawyer Balaal Khan
The family was supposed to fly to Manchester following their pilgrimage, but their husbands reported them missing when they did not return. They had last spoken to their children on 8 June.
The women's brother is understood to be fighting with extremists in Syria and it is believed the group missed a previous flight to Saudi Arabia in March after being questioned by security officials.
Bradford Council said they had not been made aware of any issues surrounding the family or the safety of their children ahead of the disappearance.
At a press conference on Tuesday Mr Iqbal made an emotional appeal to his wife Sugra, saying: "I'm shaking and I miss you. It's been too many days."
Mr Shoaib, husband of Khadija, dismissed any suggestions the sisters were in unhappy relationships saying he and his wife of 11 years had a "perfect relationship".
Syed Zubair Ahmed, the estranged husband of Zohra Dawood did not attend as he is currently in Pakistan, where he has been living for the past seven months.
'Quietly condoning IS'
|David Cameron says IS is one of the biggest threats the world has faced|
But Manzoor Moghal, chairman of the Muslim Forum, accused families of those travelling to Syria and Iraq of "endlessly pointing the finger at others" and said communities should take responsibility.
It comes as Prime Minister David Cameron has warned of the dangers posed by those who "quietly condone" Islamic State militants' extremist ideology.
Speaking at a security conference in the Slovakian capital Bratislava, he stressed the importance of tackling radicalisation at its source.
Radicalization, is the process of demonizing otherwise devout people. I'm not talking figuratively, but literally. It is literally demonic for women like these 3, to jointly go insane and take their children into a place where the sons will most likely die at an early age, and where the girls will become brides, willing or unwilling, shortly after puberty.
Nowhere, in a sane world, is such an action justified. Islam is horrifically evil! Those 'peaceful' Muslims are not the majority, they are those who have been partially assimilated into western culture, a culture that younger Muslims are rejecting in favour of more 'devout', ie radical Islam.
The west is in serious trouble and most governments are suffering from 'Ostrich Syndrome'. It may already be too late to stop them from turning Europe into an Islamic continent.