The Lebanese army has detained a wife and a son of Abu Bakr al-Baghdadi, the leader of the Islamic State in Iraq and the Levant (ISIL) group, as they crossed from Syria in recent days, security officials have said.

The military said that the wife was a Syian citizen and the detained son was nine years old.

According to the army statement, they were detained 10 days ago and have been questioned at the ministry of defence.

The Lebanese newspaper As-Safir reported the army detained her in coordination with "foreign intelligence apparatus". It said she had been travelling with a fake passport accompanied by one of her sons.

The armed ISIL group has seized wide areas of Iraq and Syria, Lebanon's neighbour to the east, declaring a "caliphate" over the territory it controls.

The Lebanese security forces have waged a crackdown on ISIL sympathisers in Lebanon and the intelligence services have been extra vigilant on the border crossings.

They have arrested over the past few months a number of ISIL fighters suspected of staging attacks to expand ISIL influence in Lebanon.

A US-led alliance is seeking to roll back ISIL's territorial gains in Iraq and Syria.