Some 50 Indonesian Islamic State fighters and their family members imprisoned in northern Syria are believed to have escaped during Turkey’s invasion of the region to oust Kurdish forces, according to a counterterrorism source. Turkey began a military assault on Syria after the United States abruptly withdrew its troops from the country last week. Of the 12,000 Isis militants held in Syrian jails, about 2,000 come from foreign countries, including Indonesia and Malaysia. The rest are mostly from Syria and Iraq. “According to our intelligence, around 50 Indonesian fighters and their families held in prison in Syria have escaped. That is our latest information,” an Indonesian counterterrorism source, who declined to be named, told the Post . Indonesia has an estimated 34 jihadist fighters and about 700 Isis family members in Syria, he said. “We have tightened up our surveillance at the airports, ports, land borders,” he said. The 12,000 jailed Isis militants in Syria are guarded by only 400 Kurdish soldiers, who also oversee a sprawling camp holding over 70,000 Isis family members. As Turkey escalates its assaults in Syria, the Kurdish guards are buckling under severe strain. On Sunday, Kurdish authorities said nearly 800 relatives of foreign Isis members escaped a displacement camp near where Kurdish forces were holding off a Turkish offensive. Ahmet Yayla, assistant professor of criminal justice from DeSales University in the US, said if the 12,000 Isis prisoners staged an uprising, they would easily be able to overpower the Kurdish guards and escape. There have already been several prison-break attempts, according to Yayla. Malaysia, Indonesia fear return of Isis fighters jailed in Syria Noor Huda Ismail, a counterterrorism expert and visiting fellow at Nanyang Technological University, said Indonesian Isis fighters were battle-hardened and their loyalty to Isis remained strong. Many of them had been filmed burning their Indonesian passports in Syria to proclaim their residence in the Caliphate. “Without proper documents, it would be hard for them to go back to the region. Almost certainly, they will disperse, especially to neighbouring countries such as the borders of Turkey, Iraq and also Iran,” Huda said. If they return home now, they will energise the existing cells of Isis who are currently lying very low Noor Huda Ismail, counterterrorism expert Huda said Isis returnees were likely to contact Indonesia’s largest pro-Isis network, the Jamaah Ansharut Daulah (JAD), if they made it home. “If they return home now, they will energise the existing cells of Isis who are currently lying very low,” she said. Yayla said Isis was looking for fake passports for its foreign fighters. “If they can find fake passports, they will want to send their experienced fighters back … so they can lead the organisations over there,” Yayla said. As the battle rages on, Turkey has vowed to maintain control of all detention centres in its operational area and work with other nations to rehabilitate Isis fighters. “We are prepared to cooperate with source countries and international organisations on the rehabilitation of foreign terrorist fighters’ spouses and children,” President Recep Tayyip Erdogan wrote recently in a Wall Street Journal editorial. Why a resurgent Jemaah Islamiah in Indonesia is also bad news for Malaysia and Singapore But according to Yayla, who was formerly a senior official of the counterterrorism and operations department in the Turkish National Police, Turkey has a “soft” stance on Isis. “In Turkey, there are around 1,000 Isis prisoners and most of them have been released very quickly,” Yayla said. “When I was the counterterrorism chief at Sanliurfa [a Turkish city that borders Syria], I received instructions from Ankara not to interrupt the flow of foreign fighters entering into Syria to join Al-Nusra Front,” he said. Al-Nusra Front has been described as the al-Qaeda of Syria and is thought to be the second strongest militant group after Isis. News of the jailbreak by Indonesian Isis militants comes as the Southeast Asian country grapples with a rising wave of extremist attacks. Last week, chief security minister Wiranto was stabbed by suspects belonging to an Isis-linked radical group – an incident which prompted Indonesia to boost security for all government officials. Police on Tuesday announced that more than 30,000 security personnel would be deployed for President Joko Widodo’s inauguration on Sunday. Indonesian minister Wiranto’s stab wound ‘reached his intestines’: adviser Police spokesman Dedi Prasetryo told reporters that at least 26 terror suspects had been arrested since the attempt on Wiranto’s life . Dedi said they had a terror plot involving four suicide bombers: “One suicide bomber in Cirebon, two in Yogya and one in Solo.” It was unclear if the four suicide bombers were among the 26 arrested. Meanwhile, the US on Monday slapped sanctions on Turkey as it demanded an end to the military operation, accusing its Nato partner of putting civilians at risk and allowing the release of extremists. At least 30 civilians have died as a result of Turkey’s offensive in northern Syria, according to the Britain-based Syrian Observatory for Human Rights on Monday. The Kurdish forces helped the US to defeat Isis in March this year, losing 11,000 of their own members, but have been left vulnerable after US President Donald Trump abruptly withdrew American forces from the region last week.