A member of Lebanon’s Security Forces confiscates computers as they carry out raids at banking institutions and financial companies in the commercial Hamra district of Beirut as part of an investigation into cash transfers to ISIS on March 8, 2017.

Lebanese authorities carried out raids Wednesday against currency exchange offices and money transfer companies on suspicion they sent huge sums to ISIS, a judicial source told AFP.

The source said the raids started Tuesday and were continuing on Wednesday against several institutions “on suspicion they transferred huge sums of money to areas controlled by ISIS in Raqqa and elsewhere,” referring to an extremist stronghold in Syria.

The source added that a number of people had been detained for investigation but were not yet formally under arrest.

“Information is being gathered on the value of the money that was transferred,” the source added. Lebanese media reported that as much as $20 million had been transferred to the jihadist group, which holds territory in Syria and Iraq, as well as Libya.

But the judicial source dismissed that figure as “exaggerated” while conceding the suspected sum was nonetheless “huge.”

On Wednesday afternoon, an AFP photographer saw security forces raiding three offices on bustling Hamra Street in the west of Beirut, and seizing documents and computer equipment.

Afterwards, the raided premises were sealed with red wax and a sign from the military prosecutor warning against their reopening “under penalty of prosecution.”

There was no official statement on the raids, or details on the number of companies that had been targeted.

Lebanon’s Central Bank imposes strict rules on financial institutions intended to prevent money laundering and terrorism financing, including caps on the amount that can be transferred overseas without additional supporting paperwork.

Lebanon has been heavily impacted by the war in neighboring Syria since it erupted in March 2011.

Security forces have on several occasions arrested suspected ISIS members, including in February, when two men were detained on accusations they were planning an attack in central Beirut.