Lebanese authorities has detained a wife and young son of Islamic State group chief Abu Bakr al-Baghdadi, the self-proclaimed "caliph" of the brutal jihadist organisation, security and military sources say.
The pair were detained by military intelligence 10 days ago near the town of Arsal close to the border with Syria, a security source said on Tuesday.
The woman is Syrian, and her son is around eight years old, according to a military source who confirmed the arrest.
It is not known how many wives and children Baghdadi has, but Islamic law allows men to marry four women and the Islamic State (IS) group has encouraged its members to wed more than once.
Lebanese daily As-Safir, which first reported the arrest, said it was carried out "in co-ordination with foreign intelligence agencies".
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It said the woman was travelling on a false passport, without saying where the document purported to be from.
The security source said the wife and child were taken to the defence ministry headquarters in Yarze, just outside the capital Beirut, "where investigations were continuing".
Baghdadi was put on the US "terrorism" watchlist in October 2011, and there is a $US10 million ($A10.82 million) bounty for his capture.
In June he was declared a "caliph" in an attempt to revive a system of rule that ended nearly 100 years ago with the fall of the Ottoman Empire.
US officials say he was born in 1971 in Iraq, and joined the insurgency that erupted shortly after the 2003 US-led invasion.
He spent time in a US military prison in the country, and is believed to have taken the reins of IS's predecessor, the Islamic State of Iraq, in 2010, after two of its chiefs were killed in a raid.
