Israel Rounds Up 400 Palestinians in Sweeping Raids : Mideast: The detainees are suspected of backing the radical Islamic group Hamas. Their arrests come amid suicide attacks by its military wing.

In a massive pre-dawn sweep Tuesday, Israeli security forces arrested more than 400 Palestinians on suspicion of supporting a radical Islamic group whose military wing has launched suicide attacks that have killed 13 Israelis this month.

Moving through Islamic strongholds in the occupied Gaza Strip and West Bank, Israeli troops and intelligence agents detained leaders and activists from Hamas, from its armed underground units--the Izzidin al Qassam Brigades--and from the Islamic Jihad.

Israeli military sources said that more than 200 men were detained from Gaza and another 200 from West Bank towns and that the sweeps were continuing.

“The aim (of the roundup) was to deliver a severe blow at the operational structure of Hamas to disrupt their operations,” said Col. Renaan Gissin, a military spokesman. “The concentrated effort was to send a clear message to Hamas that we will not let go of them and will not tolerate such activities.”

Both Hamas and Islamic Jihad strongly oppose Israel’s agreement with the Palestine Liberation Organization on Palestinian self-government. They recently intensified their attacks on Israeli targets, striking beyond the West Bank and Gaza Strip into Israel itself in an apparent attempt to disrupt the ongoing negotiations.

The roundup operation is the largest since Prime Minister Yitzhak Rabin forced 415 Muslim fundamentalists, also members of Hamas and Islamic Jihad, into exile in southern Lebanon in December, 1992--only to bring all of them back a year later under international pressure.

“We will fight those who continue terror with all the means that are available to us,” Rabin said of the new operation. “The only limitation is the limitation of the law.”

Palestinian sources said about 75 men were detained in Gaza City, about 15 in the Jabaliya refugee camp, 30 in Rafah and dozens more in Khan Yunis and Deir al Balah.

Gazans said that some of those arrested there had been detained in the past for ties to Hamas, others are relatives of suspected Hamas guerrillas and a few are relatives of Hamas leaders. Many of those for whom the troops were searching were not home and are apparently in hiding.

In Hebron in the West Bank, residents said about 25 Hamas backers were arrested. There were further arrests in Ramallah, Nablus and Bethlehem.

Dr. Mahmoud Zahar--a Hamas leader in Gaza City who was deported in 1992 but who has not been rearrested--dismissed the roundup as a Rabin effort to convince Israelis that he is indeed taking a tough line on security issues.

PLO leaders charged that the arrests were an attempt to appease Israeli public opinion and will undermine negotiations between Israel and the PLO on implementing the agreement on Palestinian autonomy.

“It will be a snag in the negotiations, but I doubt they will be stopped because of the arrests,” said Zakariya al Agha, the PLO leader in Gaza.

About 3,500 activists from Hamas--as the Islamic Resistance Movement is known in Arabic--are already in jail. The PLO is pressing in the negotiations with Israel for their release, but Israel has so far refused.

The operation actually began last week with the arrest of several hundred suspected Hamas supporters, including more than 70 Friday, as police searched for those involved in two bus bombings in Israel this month.

Hamas has declared that it will carry out five major attacks on Israeli targets to avenge the Feb. 25 massacre by a Jewish settler of Muslims praying at a mosque in Hebron. It took responsibility for the two bombings and an ax attack on Israeli buses this month. Islamic Jihad claimed a shooting attack against a bus stop.

In a leaflet released Tuesday, Hamas said that the ax attack Monday that left four Israelis wounded--two of them by gunfire directed at the attacker--was the third of the revenge attacks.

But Hamas’ hard-line opposition to Israel may be easing. A leader of the movement said in comments published Tuesday that the group is ready to make peace if Israel withdraws from the occupied territories.

Mousa abu Marzouk, with Hamas’ political office in Damascus, Syria, appeared to back away significantly from Hamas’ previous insistence on the annihilation of Israel.

“If the enemy government wants a way out of the crisis it is living through,” he reportedly told the weekly Al Sabeel, the mouthpiece of Jordan’s Muslim Brotherhood, “then we say that the way out is through a total withdrawal from the West Bank, the Gaza Strip and Jerusalem and the removal of all (Jewish) settlements in the territories.”

Hamas’ position has been that Israel’s entire Jewish population should be evacuated to Europe and the United States and an Islamic state created in its place.