Lashkar-e- Taiba was behind the Mumbai attack that left 166 people dead. (File Photo)
A Pakistani bomb-making expert linked to the 2008 Mumbai attack is among scores of trained terrorists who slipped into the EU posing as refugees to join the ISIS's plot to commit atrocities in Europe, a media report in London said on Sunday.
Muhammad Usman Ghani, who is linked to the Lashkar-e- Taiba (LeT) and Lashkar-e-Jhangvi terror groups, is being held in Austria on charges of participating in a terrorist organisation, The Sunday Times said.
The ISIS "strike team" sent to Europe before last November's Paris attacks included Usman, the veteran bomb-maker from Pakistan.
LeT was behind the Mumbai attack that left 166 people dead.
The disclosure come from sources close to a multinational investigation who warn more "large-scale" assaults on European countries, including Britain, are "imminent". Dozens of the ISIS operatives are still at large, the report said.
Usman, 34, and a suspected Algerian ISIS fighter named as Adel Haddadi, 28, have been questioned by Austrian and French authorities after being linked to the terrorist gang that killed 130 people in Paris last November.
Investigators believe both men are part of an unknown number of Isis "strike teams" that used the migrant flow to infiltrate Europe last year. A network of jihadists based on the Continent has provided extensive logistic support, from fake identity documents to safe houses.
Usman and Haddadi arrived on the Greek island of Leros on October 3 on the same boat as two of the Paris suicide bombers, known only by the fake names Ahmad al- Mohammed and Mohammad al-Mahmod. The pair blew themselves up in front of the Stade de France stadium on November 13.
All four men had obtained Syrian passports and travelled on a boat carrying 198 people, according to a Greek police report.
Adel Haddadi has been linked to the Paris attacks Usman and Haddadi were travelling under the names Faycal Alaifan and Fozi Brahi.
They were arrested by Greek police soon after arriving because their documents showed up on the EU's database of nearly 4,000 passports that had been stolen by ISIS.
Greek police released both men on October 28 and allowed them to continue the journey across Europe.
Shortly after the Paris attacks, Usman and Haddadi resurfaced in Austria, applying for asylum at the Asfinag refugee shelter, near Salzburg, in late November.
Local police then arrested the men on December 10 when a fingerprint search linked them to the passports commandeered by ISIS.
Investigators are trying to determine whether the arrests in Greece had prevented them from joining the Paris attackers, or whether they were planning a separate assault.
An examination of phones in their possession in Austria revealed that the suspects had dialled numbers used by their suicide bomber travelling companions, as well as associates of Abdelhamid Abaaoud, the suspected ringleader of the terrorist cell behind the attacks.
Abaaoud, who was killed in Paris in a shootout with police on November 18, boasted to an associate he and another 90 fighters had slipped into Europe as refugees, according to French investigators.
While in detention in Austria, Usman and Haddadi have been questioned by members of the DGSI, France's internal security service - the equivalent of MI5.
Both men are expected to be extradited to France to stand trial on charges relating to the Paris attacks. They are denying the charges.