Maryam Kallis was apparently arrested in Syria on 15 March 2009
A mother has been missing for more than two weeks since her arrest in Syria, her British husband has said.
Maryam Kallis, 36, was handcuffed on a busy street in Damascus in front of her young son and has not been seen since, her husband Masood told the BBC.
They were brought back to her apartment where their passports were taken, then she was forced to leave, he added.
Amnesty International says it has "serious concerns" about her safety. The Foreign Office is investigating.
The mother-of-four had three of her children, aged five to eight, staying with her at her sister's home in Syria.
Mr Kallis says the youngsters, who all have British passports, have been left traumatised by events.
"The children cannot sometimes explain themselves - but the feelings you can only imagine," he told the BBC at his flat in London.
"One of my daughters said 'Why have they taken Mummy? The police have taken Mummy; why have they taken her?'... what do you say to her?
Masood Kallis describes his wife's 'arrest'
"These are British citizens in a vulnerable state in a vulnerable area and nobody has bothered to go round and say 'listen, we're here for you, be patient' - comforting words."
Mrs Kallis first moved to the Syrian capital with her family in 2002 to study Arabic.
She came back to the UK in 2008 but returned to Damascus in March this year to collect her children and bring them home.
Her husband says he has no idea why she was detained on 15 March but thinks the Syrian security services may have been responsible.
"Her sister who lives with her opened the door and saw her handcuffed, with eight to 10 men with them," he said.
"They were barging into her house, took the passports off the children, off Maryam, off her sister as well as other documents and took Maryam away by force in front of the children."
He said she has not been seen since.
Human rights group Amnesty International has expressed serious concern about her safety and welfare and fears she may be in danger of torture.
Amnesty supporters have called on the Syrian authorities to immediately release her unless she is charged with a recognisable criminal offence.
They have also demanded access to a lawyer of her own choosing, her family and any medical treatment she may require.
UK campaigns director Tim Hancock said: "The Syrian security services have a long and very troubling record of detaining people in secret for weeks, months or even years on end and subjecting them to torture.
"The important thing now is that British consular officials, a lawyer and her family are given proper access to Maryam and that her detention is regularised.
The Foreign Office says it has asked the Syrian authorities for access to Mrs Kallis as a matter of urgency.
The Syrian embassy in London said in a statement: "We have been approached by the Foreign Office to look into the alleged disappearance.
"We are taking this matter seriously and we are in the process of looking into it... with the relevant authorities in Syria."
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