Past Points to Islamic Extremists : Egypt: Attack believed to be part of battle by fundamentalists to topple secular government.

The assassination attempt against President Hosni Mubarak marks a major escalation in the three-year Egyptian insurgency, which has defied ruthless, often bloody attempts to quash it, Middle East experts and counterterrorism officials here said Monday.

Although no group has claimed responsibility for the attack in Ethiopia--the most daring and sophisticated of several recent plots against Mubarak--Islamic extremists are widely believed to be responsible. “Because of their recent record, that’s the working assumption,” an Egyptian official said Monday.

In Egypt, the battle lines between a secular authoritarian state and Islamic activists demanding change date to the troubled months before the 1981 assassination of President Anwar Sadat. Despite a massive crackdown and subsequent trials, Islamic extremists have also proven to be Mubarak’s biggest challenge. But even within that category, there is an array of possibilities, inside and outside Egypt.

Mubarak on Monday indicated a Sudanese link, a possibility strengthened with the reported arrest of at least two Sudanese, according to U.S. officials. The Islamic government of Lt. Gen. Omar Hassan Ahmed Bashir in Khartoum has tense relations with neighboring Egypt because Sudan has trained and sheltered a range of extremists from several nations, including Egypt. Sudan also has close ties with and receives support from Iran.

In Egypt, the two most active groups are the Vanguards of Conquest and the Gamaa al Islamiya (Islamic Group).

The Vanguards of Conquest is a military wing of Jihad, which was responsible for the Sadat assassination. After trials in the early 1980s led to the imprisonment, elimination or exile of many Jihad members, the movement was revived.

In a statement read to an international news agency after the attack, a caller said the Vanguards would continue to seek Mubarak’s death. But the statement fell short of claiming responsibility for Monday’s attack.

The new Jihad is led by Dr. Ayman Zawahiri from bases outside Egypt, and many of its members look to Sheik Omar Abdel Rahman as their spiritual mentor. Abdel Rahman is now on trial in New York for links to a group plotting to kill Mubarak and to bomb the United Nations and other New York landmarks. Many of the World Trade Center bombers also worshiped at the mosque where he preached.

Jihad is also sophisticated technically, especially in its use of car bombs. But the Vanguards have not been active in the last year because of the government crackdown, U.S. officials said.

*

Since 1992, several cells that come under the umbrella of the Gamaa al Islamiya have also waged an increasingly violent campaign against the Egyptian government. The group is associated with the 1990 assassination of the Speaker of Egypt’s Parliament. But it generally targets lower-level officials, police, Coptic Christians and Western tourists. The group has been active in major cities and rural areas, although it is associated with much of the recent violence in El Minah and Asyut in Upper Egypt.

Before Monday’s attack, Egypt claimed to have crushed the infrastructure of the major Islamist groups. Tens of thousands of police deployed to put down the insurgency did quell much of the violence in major cities and tourist areas, although Upper Egypt remains volatile. But the cost has been high. Mubarak’s regime has come under increasing criticism for human rights abuses.

A 1995 Human Rights Watch report charged Egypt with extrajudicial executions, excessive force, the death in detention of suspects and “systematically” taking hostage suspects’ relatives, including elderly women and children, to induce them to surrender.

Public backlash from the crackdown and the government’s inability to deal with the miserable economic and social conditions of millions of Egyptians may be leading to further alienation--and fueling rather than removing the problem, U.S. officials add.

Times staff writer Robert L. Jackson contributed to this report.