CAIRO - Islamic State, fighting to redraw the map of the Middle East, has been coaching Egypt's most dangerous militant group, complicating efforts to stabilize the biggest Arab nation.
Confirmation that Islamic Sate, currently the most successful of the region's jihadi groups, is extending its influence to Egypt will sound alarm bells in Cairo, where the authorities are already facing a security challenge from home-grown militants.
A senior commander from the Sinai-based Ansar Bayt al-Maqdis, which has killed hundreds of members of the Egyptian security forces over the last year, said Islamic State has provided instructions on how to operate more effectively.
"They teach us how to carry out operations. We communicate through the internet," the commander, who asked to remain anonymous, told Reuters.
"They don't give us weapons or fighters. But they teach us how to create secret cells, consisting of five people. Only one person has contact with other cells."
Militant groups and the Egyptian state are old foes. Some of al-Qaida's most notorious commanders, including its current leader Ayman al-Zawahri, are Egyptian.
One Egyptian president after another has crushed militant groups but they have always resurfaced.
The success of Islamic State in seizing large parts of Syria and Iraq has raised concerns in Egypt, where authorities are battling Ansar as well as militants who have capitalized on the chaos in post-Gaddafi Libya to set up over the border.
Islamic State became the first jihadi group to defeat an Arab army in a major operation after steamrolling through northern Iraq in June almost unopposed by the Iraqi military.
Unlike al-Qaida, which specializes in hit and run operations and suicide bombings, Islamic State acts like an army, seizing and holding territory, a new kind of challenge for Western-backed Arab states.
Army offensives have squeezed Ansar, forcing its members to flee to other parts of Egypt, the commander said. But it still poses a security threat.
President Abdel Fattah al-Sisi has expressed concerns about militants over the Libyan frontier. Security officials say these groups are inspired by Islamic State, an offshoot of al-Qaida notorious for beheadings and mass executions, most recently of American journalists James Foley and Steven Sotloff.
Sisi, who as army chief toppled Islamist President Mohamed Morsi last year after mass protests against his rule and then cracked down on his Muslim Brotherhood, has restored some political stability.
But militant groups still present a major challenge. Security officials say thousands of Egyptian militants have joined Islamic State's jihad in Iraq and Syria and authorities are concerned they could return home to fight the government.
That would pile pressure on Egyptian security forces who have failed to end a campaign of bombings and shootings which killed hundreds of soldiers and police since Morsi's fall.
Egyptian security officials say leaders of Islamic State and Ansar have established contacts. Meanwhile, militants based in Libya have also forged ties with Ansar, creating a complex web.