An Islamist lawyer and Egyptian security officials said for the first time Wednesday that they knew the real identity of the shadowy leader of Al Qaeda in Iraq, as skepticism grew over claims that he had been killed in fighting there.

U.S. authorities urged caution about reports that Abu Ayyub al-Masri — also known as Abu Hamza al-Muhajer — had died. An insurgent coalition insisted in a Web posting that he was alive but offered no proof.

In Cairo, Islamist lawyer Montasser el-Zayat, said al-Masri was in fact Abdel Monem Ezzedine Ali Ismail, an Egyptian bomb expert and a former member of the militant Islamic Jihad group which is headed by Usama bin Ladin's deputy Aymen al-Zawahiri.

The lawyer, himself a former member of the Egyptian militant Gamaa Islamiya group, said that al-Masri has used several other pseudonyms in the past, including Abu Ayyub, Abu Jihad, Youssef Hadad, and Labeeb Hadad.

El-Zayat cited official papers and court documents which said that Ismail was born on Dec. 21, 1969, in Nile Delta province of el-Sharqiya and left school there before he joined the Islamic Jihad group.

In 1999, Ismail was sentenced for seven years in absentia for terrorist activities, el-Zayat told The Associated Press.

Egyptian security officials confirmed al-Zayat's identification of al-Masri, and said he has been investigated for links with Egyptian activists who have been requiting volunteers to fight in Iraq.

The officials, speaking on condition of anonymity because of the sensitivity of the investigation, said a detained Egyptian lawyer is being questioned for possible links with Ismail.

It appeared this investigation had led to the conclusion that al-Masri and Ismail were the same person. However, neither el-Zayat nor the security officials provided details.

Egypt's state-owned Al Ahram newspaper reported Wednesday that Ismail spent some time in Iran before he was sent by Al Qaeda to lead the group in Iraq.

Al-Masri, an Egyptian militant, took over leadership of the Sunni terror network and was endorsed by Usama bin Laden after Abu Musab al-Zarqawi was killed last June by a U.S. airstrike in Diyala province.

In recent months, divisions among Sunni insurgent groups have sharpened, in part because of Al Qaeda's attempt to dominate the insurgency, impose a harsh brand of Islam and use foreign fighters, U.S. officials say.

More than 200 Sunni Arab sheiks in Anbar province decided to form a political party to oppose the al-Qaida. Clashes have also erupted in three Sunni provinces in Iraq between Al Qaeda and other insurgent groups, including the nationalist 1920 Revolution Brigades, U.S. officers say.

The Islamic State of Iraq, the umbrella organization that includes Al Qaeda in Iraq, said it published the denial of al-Masri's death "to reassure the hearts of Muslims." Last month, the organization announced an "Islamic Cabinet" for Iraq and named al-Masri as "minister of war."

According to associates in Afghanistan, al-Masri has been involved in Islamic extremist movements since 1982, when he joined Islamic Jihad, a terror group led by al-Zawahri, who became bin Laden's chief deputy.

Al-Masri fought with Muslim rebels against the Soviets in Afghanistan in the 1980s and later ran al-Qaida training camps there.