Western ISIS recruits kept far apart from each other because they knew some were targets for drone strike assassinations.

"A lot of the westerners were kept distances from one another because one of the primary affairs was targeted drone strikes," British recruit Hamza Parvez told the BBC from prison in Syria.

"People wouldn't want to be associated with one another just in case. So we'd really be scared of, ok, 'this guy might be,' and 'this guy might be'."

The physical defeat of ISIS forces in Syria was declared on March 23 and a number of captured western recruits have spoken to media since about the caliphate's final days.

ISIS terrorists recruited from western countries like the US and UK always kept their distance from each other because of the threat of drone strikes, according to a captured member of the terror group.

"A lot of the westerners were kept distances from one another because one of the primary affairs was targeted drone strikes," captured ISIS member and ex-police cadet from London, Hamza Parvez, told the BBC from a Kurdish prison in Syria.

Parvez left the UK to join ISIS in 2014 but was captured in Baghuz, the final ISIS bastion in Syria, according to the BBC. The government has stripped him of citizenship.

A U.S. Predator drone flies over Kandahar Air Field, southern Afghanistan on a moonlit night. AP Photo/Kirsty Wigglesworth

In an interview from prison he described the extreme fear among western members about being killed the drones.

"So, people wouldn't want to be associated with one another just in case."

"Because we didn't actually have the list of who's on the drone list or not. So we'd really be scared of, OK, this guy might be, and this guy might be."

"So it's better I just keep to myself," he said.

A number of key ISIS figures have been killed in drone strikes.

Hamza Parvez. BBC

They include media director Abu Anas al-Faransi in March 2019, British ISIS fighter Mohammed Emwazi, known as "Jihadi John," in December 2015, and British defector Sally Jones in October 2017.

Parvez also told BBC reporter Quentin Sommerville that he regrets joining, wants to come home, and never knew the "realities" of being part of ISIS.

"I didn't know there was something waiting for me like that so most of the foreign fighters, when you do talk to them, the first thing they say to you is that we would never ever have come if we had known the realities of ISIS," he said.

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"There was many times where I thought 'time to pack up and leave,' and there's many times I did try to pack up and leave but the reality was that it wasn't as easy as it sounds."

ISIS forces in Syria were declared defeated by joint US and Kurdish forces on March 23. Since then a number of western recruits have spoken to media about the caliphate's final days from prison. ISIS members in the last occupied neighborhood in the village of Baghouz, Deir Al Zor province, Syria, March 10, 2019. The caliphate was declared eliminated in Syria on March 23. REUTERS/Rodi Said

General Mazloum Kobani, the commander-in-chief of the Kurdish-led Syrian Democratic Forces, said that his forces liberated the last ISIS stronghold in the village of Baghuz, ending the terror cell's presence in Syria.

ISIS is still active in Iraq, and parts of Africa.

In recent weeks, apologetic ISIS brides from the US, Europe, and Canada have attempted to secure their safe return to the west after defecting to ISIS.

The Syrian government has called for western countries to take back their ISIS members.