Women and children in the largest Islamic State detention centre in Kurdish-controlled Syria are expecting to be freed in the wake of a Turkish assault on the area, according to people inside the camp.

Al-Hawl, home to about 60,000 women and children with links to Isis and 10,000 displaced civilians, has been tense since Donald Trump announced US troops would leave the area at the weekend, paving the way for the Turkish attack on Wednesday.

Radicalised women, including some who have been accused of killing other prisoners they say are not adhering to Isis’s strict ideology, believe Isis sleeper cells in the area will attack the Kurdish guards and free those inside in the next two days, a woman who has been held alongside them said via WhatsApp message.

“They know the Turkish campaign has begun,” the woman said. “After living in this horrible place for months they are ready to take this opportunity to break out.”

About 90,000 men, women and children from Isis’ former “caliphate” are currently in the custody of the US-backed Kurdish-led Syrian Democratic Forces (SDF). Their fate was thrown into question by Trump’s announcement that he would withdraw the 1,000 US special forces in the area, effectively removing the buffer that has stopped Turkey attacking the SDF.

Ankara said the SDF is affiliated to the outlawed Kurdistan Workers’ party (PKK), which has fought an insurgency against the Turkish state since the 1980s. Trump’s decision was widely criticised as a betrayal of the force that did the bulk of the ground fighting against Isis in Syria, and was one that risked new fighting in the eight-year-old war and could lead to Isis’s resurgence.

Isis has already claimed a twin suicide attack in the early hours of Wednesday in its former capital Raqqa, which killed and injured 25 people.

SDF officials have repeatedly warned their camps and prisons are overflowing, calling on other countries to repatriate some 20,000 foreigners currently under their watch.

Most facilities are chronically understaffed: during a July visit by the Guardian to al-Hawl, there were only 400 guards to keep order over about 70,000 people in the camp.

A new alarm was raised over the poor security at al-Hawl and other camps and prisons after SDF spokesperson Mustafa Bali said earlier this week that some of the soldiers currently guarding Isis fighters and their families would be redeployed to the border area to fight off the anticipated Turkish attack.

A source who often visits the camp said there were no signs that the SDF had redeployed any soldiers from al-Hawl, but nonetheless the camp was more volatile than usual.

Violence at al-Hawl has ebbed and flowed since the camp became home to an unexpected influx of women and children after Isis was driven out of the remnants of its territorial “caliphate” earlier this year. Riots are common, and at least one guard has died after being stabbed. Last week, an improvised explosive device was discovered there.

In justifying the green light he gave to the Turkish invasion, Trump stressed his belief that Turkey would take on the burden of captured Isis members. However, al-Hawl is outside Turkey’s proposed 32km buffer zone on the border, and US and Turkish officials have not shared details on how such a huge transfer of people between warring parties would be executed.

Trump has also appeared preoccupied that the US would have to pick up the bill for the custody and prosecution of detained European Isis fighters, and the care of their families.

On Thursday, he returned to the theme several times in explaining his thinking on Syria.

“We said to France, we said to Germany, we said to various countries in Europe: We’d like you to take your people back,” Trump told reporters, saying that European capitals had refused. He then suggested it would be fault of those governments if European Isis fighters escaped back to their homelands.

“Well, they’re going to be escaping to Europe. That’s where they want to go,” he said. “Europe didn’t want them from us. .. They could have had trials, they could have done whatever they wanted. But as usual, it’s not reciprocal.”

European officials insist the US was never going to have to pay, and that Trump’s response to Recep Tayyip Erdoğan’s request for acquiescence in his planned offensive might have been based, at least in part, on a misunderstanding of the status of the Isis prisoner issue.

At the time the Turkish offensive began, the US, France, Germany and other European countries whose nationals had joined Isis, had been exploring ways of prosecuting Isis fighters in the region, most likely in Iraq. It was officially called the “regional prosecution pathway”.

“We never expected the US to take them back on to US soil, and we definitely did not want them taken to Guantanamo,” a European official said, expressing surprise at the president’s remarks, as the Europeans and the US had been in constant and continuing discussions about the fate of the Isis captives.

The official said the reason European fighters were not being taken back by their own countries was not about cost, but about the difficulties of prosecuting them.

“It is a question of due process,” the official said. “Courts at home would throw out cases of detainees captured on the battlefield.”