The leader of Turkey's military coup, Gen Kenan Evren, announced on Turkish television today that his ruling five-man National Security Committee would soon start drafting a new constitution aimed in part at charging the country's laws on elections and political parties.

Evren, the military chief of staff and a political moderate, promised a return to elected civilian rule, but gave no indication of when that might happen. He also said Turkey would maintain its pro-Western foreign policy and would abide by all its commitments, including those to the North Atlantic Treaty Organization.

The general made the announcement after ousting Prime Minister Suleyman Demirel early today in a bloodless coup that he said was designed to restore stability to a country wracked by political and sectarian strife.

Helicopters clattered above the capital in the predawn hours, and hundreds of troops with armored personnel carriers and tanks cleared the streets. Sources said military buses rounded up deputies of the National Assembly. By dawn, the city looked deserted except for troops. By late morning, some Turks ventured out to Army-supplied bread stores, and long lines formed for food.

The commanders announced that the takeover, after five years of increasing violence in which more than 4,000 persons have died, was aimed at preventing "a possible civil war" in the NATO-member country.

The Ankara Martial Law Command said in a communique that Demirel, leader of the conservative Justice Party, and the main opposition leader, former prime minister Bulent Ecevit, leader of the left-of-center Republican People's Party, "were interned" in their homes.

Necmettin Erbakan, chief of the Moslem fundamentalist National Salvation Party, was "under the protection and custody" of the military, the communique added.

The five-man National Security Committee that took over the government is headed by Evren and the commanders of the ground forces, Air Force, Navy and gendarmerie.

It was the third time in 20 years the armed forces have intervened to try to enforce political stability. Evren and the other four military commanders, in a statement nine months ago criticizing the political instability and violence, indicated they were prepared to intervene again.

The troops moved through the country's cities shortly after midnight, set up roadblocks and took control of the streets. The coup was announced at 4:15 a.m. by the state radio. It said martial law, in effect already in a third of the country, had been extended over the rest, an indefinite curfew was in force, airports and the frontiers were closed, parliament and all political parties were dissolved, all political activity was banned and the political immunity of members of parliament was abolished.

Alparslan Turkes, the leader of the extreme right-wing Nationalist Action Party, was not at home when troops went to detain him, and the junta called on him to give himself up "for his own security."

Turkes was one of the colonels who led the Turkish republic's first military coup, also bloodless in 1960. Turkey's only other military coup was in 1971, when Demirel was ousted as premier for the first time.

An indefinite curfew imposed early this morning was lifted for 4 1/2 hours this afternoon, and people began strolling the streets and shopping for the weekend.

All exits from the country were blocked, with a few exceptions for foreign travelers in transit and Turkish workers returning to their jobs in Western Europe.

In a clear warning to the politicians two weeks ago, Evren said a weakening of state authority was helping spread terrorism and anarchy.

He and other military leaders had issued statements urging the government and the opposition parties to stop squabbling and begin a dialogue to solve Turkey's two major problems, political violence and a debt-ridden economy.

Diplomatic sources said they believed more than 100 members of parliament had been detained by troops during the day. Some trade union leaders and other controversial figures had also been detained for questioning, they said.

Evren, a soft-spoken figure widely respected across Turkey's political spectrum, said changes would be made in the constitution "to prohibit the degeneration of the parliamentary system."

He said the laws on elections and political parties would also be changed before the military handed over power to a civilian government "which respects the principles of a libertarian, democratic, secular order of law . . . ."

"Until then, all political activities have been stopped," he added.

One of many military communiques issued today said the country's extreme left-wing trade union confererations were now banned. The biggest confederation, the conservative Turk-Is, was not affected.

All associations other than welfare groups such as the Red Crescent, Turkey's equivalent of the Red Cross, were banned. These included sports clubs, meaning a suspension of soccer and other popular sports.

The junta indicated it was getting immediately down to business on the economic problems when it called in Central Bank Governor Ismail Hakki Alydinoglu and Demirel's chief economic adviser, Turgut Ozal, today for consultations.

It also declared that local and foreign press would be free to print and broadcast without restrictions.

The United States has approximately 4,900 military personnel -- mostly members of the Air Force -- in Turkey, and the State Department in Washington said its embassy in Ankara reported "there was no violence and no danger to Americans."

Meanwhile, in spite of the military curfew, children continued to play soccer in the streets of the Turkish capital today and their parents enjoyed an unexpected day off.

The relaxed scenes were in sharp contrast to the tanks, armored cars and foot soldiers now patrolling the main streets of Ankara.

The atmosphere was peaceful and almost friendly in the city center despite the dozens of tanks at key buildings and major intersections and the thousands of troops in combat gear.

Soldiers manning roadblocks smiled, saluted and waved a reporter on as he drove down the central tree-lined Ataturk Boulevard.

U.S. built Korean War-vintage M48 tanks sat at main crossroads. Tanks were strategically located around the sprawling grounds of the Meclis (parliament).

Tanks sat outside the U.S. Embassy, but the real object of their surveillance was the headquarters of the state radio and television across the street. Soldiers wearing black berets manned machine guns on the tank turrets.

In the sidestreets, children threw frisbees, enjoying the lack of traffic and the hot morning sun.

Other residents watered their gardens or strolled around, exchanging opinions on the coup.

Most people seemed oblivious to the coup, enjoying a day off from work. The atmosphere was one of quiet resignation rather than or surprise or despondency.

A group of young men standing on a street corner said they were disappointed by the takeover, however.

"It's the end of democracy," one said, but added: "Mind you, it was a pretty false kind of democracy we were being served up lately. The Turkish people deserve better politicians."