Concern grew Wednesday for 12 family members from England suspected of travelling to join Islamic State jihadists as police said that they may already be in Syria.

Two of the fathers whose wives and children went missing after first travelling to Saudi Arabia on a pilgrimage have made a tearful appeal for their return.

The family members -- the youngest aged three -- were due to return home last week but are believed to have flown from Saudi Arabia to Turkey and then crossed into Syria.

"We have received information that contact has been made with the family in the UK which suggests one of the missing adults may be in Syria," West Yorkshire police said in a statement.

"Contact has been made by one of the missing women and there is an indication that they may have already crossed the border into Syria but this is uncorroborated."

Sisters Sugra Dawood, 34, Zohra Dawood, 33, and Khadija Dawood, 30, travelled from their home in Bradford in northern England to the Saudi pilgrimage city of Medina with their nine children, aged three to 15, on May 28.

"All of you, I can't live without you," said Akhtar Iqbal, husband of Sugra Dawood at an emotional press conference on Tuesday.

Mohammed Shoaib, husband of Khadija Dawood, said: "Please contact me whenever you want. Please come back."

Zohra Dawood's husband is currently in Pakistan, British media reported.

Balaal Khan, a lawyer for the children's fathers, said the sisters were believed to have a relative fighting for either the Islamic State group or another extremist organisation in Syria, and it was feared that they have gone to see him.

The counter-terrorism unit of the regional police force is leading the investigation.

AFP