Nablus Mayor Bassam Shaka; in defiance of a gag order issued by the Israeli military governor of the occupied West Bank, said today that the Palestinian nationalist movement has reached a "decisive stage" in the wake of last week's ambush killings in Hebron, because West Bank Arabs are ready to resist occupation without guidance from their leaders.

"The Israeli behavior and policy will lead to more tensions and a harder struggle and will have a serious effect in the occupied territories," Shaka said in his first interview since the military government expelled three outspoken Hebron Arab leaders and ordered other West Bank public figures to curtail nationalist declarations.

Following Friday's machine-gun and hand grenade attack in Hebron, in which six Jewish religious students died and 16 others were wounded, the military governor expelled Hebron Mayor Fahd Kawasme, Halhoul Mayor Mohammed Milhem and Hebron's religious leader, Sheik Rajab Tamimi, and placed severe restrictions on other West Banks leaders, including Shaka. a

They are prohibited from making public speeches, attending meetings, issuing press statements and traveling outside their cities for any reason.

When asked how he intended to organize resistance to the occupation under such restrictions, Shaka said, "I can't give you a proper reply, because the struggle is not going according to plan, so that the people don't know exactly what is going to happen. Our national leadership does not now officially exist.

"But if we [the mayors] don't speak and give guidance, the people will act themselves. The people are not afraid. What we are being faced with gives us no chance to be afraid," Shaka added.

The content of Shaka's comments, the tone of which is familiar to followers of West Bank developments, is not nearly as significant as the fact that he was willing to make them on the record just five days after Israeli Prime Minister Menachem Begin and Defense Minister Ezer Weizman personally approved a get-touch policy toward any public declarations by West Bank leaders that could be construed as inciting nationalistic fervor.

Just as Friday's attack in Hebron appeared to cross a Rubicon -- a tacit understanding that kept Palestinian resistance from flaring into open guerrilla warfare waged by local residents in the West Bank -- Israel's response in expelling three leading Arab figures represented the laying down of new ground rules against political dissent.

Shaka stressed in the interview, for which he was sought out, that he was answering specific inquiries and not making public declarations on his own initiative, which he said is prohibited under the new restrictions imposed after the Hebron killings. He spoke in Arabic through an interpreter.

"I'm banned from talking, you see. But you oblige me to answer your questions," Shaka said.

Shaka, the titular head of the Palestinian National Guidance Council, said that although the council had not yet been formally banned, "it is clear the authorities have completely rejected all nationalist activities, including the guidance council." The group was formed after the Camp David accords to promote West Bank nationalism and coordinate opposition to the proposed autonomy scheme.

Shaka said public assemblies in the West Bank have been banned, mayors are prevented from traveling to other towns, and that his telephone service has been disrupted on occasion.

"But the people will find other ways and means to resist . . . In using their old wit and cleverness, which is outdated, the Israelis want to force our people to be soft and accept Camp David policies that comes from their misunderstanding of the principles of coexistence," Shaka said.

When asked if her personally feared expulsion, Shaka replied, "If my existence is threatened, for what should I be afraid? I'm not afraid what will happen. I would much prefer to stay here with my family and my people than to be deported. But not at any price." h

Last November, Shaka was jailed and almost deported, until an Israeli court intervened, because he allegedly made inflammatory statements in private conversation with Brig. Gen. Binyamin Ben-Eliezer, West Bank military commander.

Shaka disclosed that West Bank mayors, religious leaders and other public figures had drafted a communique to be sent to U.N. Secretary General Kurt Waldheim protesting last week's deportations and opposing "the Camp David conspiracy and autonomy in all its forms."

The message rejects "the transfornation of our municipal councils into offices to serve the interests of the enemy plans," and ends with the following declarations: "Long live the peoples' unity under the leadership of the (Palestine Liberation Organization) . . . Down with Camp David accords . . . Glory and eternity to our fallen martyrs."

Meanwhile, the 1,300-member student body of Bir Zeit University, near Ramallah, voted today to strike to allow students to return to their villages and organize "civil disobedience."