The father of two teenagers killed in war-torn Syria has said he fears for the future of their 20-year-old brother who remains in the country.

Abubaker Deghayes, whose 17-year-old son Jaffar was shot by President Bashar al-Assad's forces near the city of Aleppo at the weekend and whose other son Abdullah, 18, was killed in Latakia province in April, said his son Amer will not give him any indication as to whether he will return to the family home in Saltdean.

Mr Deghayes said: "The last time I heard from him was on Tuesday.

"He never says no to me when I ask him: 'Are you going to come back?' but he will not give me any answer as to whether he will come back to the UK.

"What has been given to us has also been taken away, but life is a test and we are being tested."

His comments came shortly after Jaffar's sister, Aiosha Deghayes, posted a tribute to her brother on Facebook which said he died "an honourable man helping fight an oppressive tyrant".

She described her brother as a "very quiet boy" who liked drawing, colouring or playing with a small toy as a youngster.

Miss Deghayes said: "Growing up he was always more interested in getting his homework done and watching TV.

"The opposite of my other brothers who loved playing outside and would always plot to distract my parents and run away to the park (in England) and Amo munders house (in Dahra)."

She said her brother was "always strong about what he believed in" and that "if he believed something was wrong then he would work so hard to change it".

She said Jaffar had become a troubled teenager and that "he wanted to quit the life he lived" so he changed his behaviour.

She said: "Mashallah (God willed it) he did change, from then on he did not miss a single day at college, he would spend his free time at the gym or with a good friend/his cousin, he also started going to Arabic school (learn how to read and write in Arabic) every Saturday to keep off the streets. I was so proud of him.

"As a brother he was and still is very special to me.

"He was so sweet and caring he only called me by my nickname.

"When away in the UAE (United Arab Emirates) he would constantly message me and when in England we would spend most of the summer staying up at night talking.

"England wasn't the same this summer without him.

"I wrote all this cuz (sic) Jaffar was and still is so special to me and the thought of him gone is unbearable."

Mr Deghayes claimed that the Government's strategy for dealing with Britons who travel to Syria was "criminalising" young people and must be changed.

He said he had tried to bring his sons back home to Britain but had been prevented from doing so because his passport had been taken for five or six months.

He told Sky News: "If I wanted to join the fight in Syria, I could have done that.

"I have been to that country five or six times and stayed there carrying out aid work."

Jaffar left home earlier this year in a bid to overthrow the Syrian dictator, while Abdullah left the UK in January to reportedly take up arms with Jabhat al-Nusra, an al-Qaida-affiliated group.

Their father, who said his grief at their deaths "cannot be described", claimed many people who have gone to Syria are "youngsters who made a mistake and it should be dealt with like that".

He urged the Government to re-think its tactics in dealing with those who travel there and said: "Do not push them to be radicalised, used by groups like Isis who are out for revenge and thirst for blood.

"You should have a strategy where we teach youngsters here in this country to work in relief work and to know and to experience how to help in a civilised manner.

"And also have an exit strategy for those who went there. They can't come back without the fear of their own people, their own government.

"They should be treated like youngsters who made a mistake and it should be dealt with like that, not just sent to prison. The stick of the law does not work all the time."

Mr Deghayes also appealed to all young Muslims who were thinking of travelling to Syria not to go and not to put their families through "what we are going through".

The Deghayes brothers are the nephews of Omar Deghayes, who was held by the United States as an enemy combatant at Guantanamo Bay detention camp between 2002 and 2007 after he was arrested in Pakistan.

Following the death of Abdullah earlier this year, counter-terrorism officers raided the Deghayes' family home in May and seized material after a warrant was issued under the Terrorism Act 2000.