Arrest is described as ‘high-value catch’ and reportedly follows information provided by western intelligence agencies

The Lebanese army says it has detained the second wife of the Islamic State (Isis) leader, Abu Bakr al-Baghdadi, and their eight-year-old son near the Syrian border.

The arrest reportedly took place in the past week and followed information provided by western intelligence agencies in the past fortnight.

Lebanese security officials described the woman as a “high-value catch” and said the identity of the boy was confirmed through DNA testing. If so, the revelation would support the claim of international involvement. The US and other states have samples of Baghdadi’s DNA from the nine months he spent in US custody in Iraq in 2004.

The British Foreign Office said it had nothing to add to the reports.

Analysts in Iraq said that, if true, the arrest would not necessarily yield useful intelligence. The self-styled leader of the new Islamic caliphate, which covers part of eastern Syria and Iraq, operates in an exclusively male world where women are rarely empowered. Baghdadi is believed to have three wives, two of them Iraqi and one Syrian.

“It is close to impossible that she would have operational details,” said an Iraqi intelligence officer. “But she could still be useful on things like locations.”

Baghdadi is known to move frequently across Iraq’s north-west, where he has been the target of an intensive technical effort to track him by the US National Security Agency and Britain’s GCHQ. He uses trusted couriers to pass vital information, often in written letters, or repeated orally. The FBI has put a $10m (£6.4m) bounty on Baghdadi’s head.

Al-Safir, the Lebanese news magazine, which first reported the arrest, said the woman and her son were arrested near the restive border town of Arsal and were being detained at Lebanon’s military headquarters in the hills overlooking Beirut.

The woman was identified as Saja al-Dulaimi, an Iraqi, by a Lebanese security official and a senior political source. Dulaimi was one of 150 women released from a Syrian government jail in March as part of a prisoner swap that led to the release of 13 nuns taken captive by al-Qaida-linked militants in Syria, according to media reports at the time.

The arrest could be used as a bargaining chip against Isis, which has captured many foreign, Iraqi and Syrian prisoners. There was no immediate reaction on Isis websites, but in a possible Isis reprisal at least six Lebanese soldiers were killed on Tuesday by gunmen from Syria who attacked an army patrol near the border.

Isis continues to pose a mortal threat to Iraq’s central government and to the opposition and regime in Syria where a devastating civil war is nearing its fourth year. The Iraqi and Syrian militaries have tried to mount counteroffensives against the group in past weeks, with mixed success. However, neither they nor US-led air strikes have wound back the spectacular gains the group enjoyed from June to August when it rampaged through northern Iraq as the Iraqi army withdrew.

Meanwhile, Isis supporters released a video claiming responsibility for a shooting that wounded a Danish citizen in the Saudi capital of Riyadh last month.

The video posted online by the Al-Battar Media Foundation shows a gunman pulling up beside a vehicle and firing five times at the man in the car, identified as Thomas Hoepner. The video’s authenticity could not be confirmed but it was posted on a website commonly used by militants.

Saudi security officials say a Danish man was shot while driving November 22, and that he was treated for shoulder wounds. They did not release his name.

If confirmed, the shooting would be the first attack on foreigners in the kingdom carried out by IS supporters. About a decade ago, al-Qaida militants seeking to topple the Western-allied monarchy launched a wave of attacks that killed scores of security forces and Westerners in Saudi Arabia.

The video also includes audio clips of IS group leaders calling on supporters to launch attacks inside the kingdom.

In Brussels, Danish Foreign Minister Martin Lidegaard told reporters on Tuesday that “the Dane is doing better.”

Denmark and Saudi Arabia are part of the US-led coalition conducting airstrikes against IS militants in Iraq and Syria.