Secretary General Kofi Annan today issued a call to the world's governments to be prepared for a new era of U.N. interventionism, just hours after an Australian-led multinational force touched down in East Timor to end weeks of violence.

The remarks, made in a speech marking the opening of U.N. General Assembly debate, come as the United Nations expands its role in peacekeeping operations from Kosovo to East Timor. It set the tone for the debate, an annual diplomatic speechfest for world leaders.

"There are a great number of peoples who need more than just words of sympathy from the international community," Annan said. "They need a real and sustained commitment to help end their cycles of violence, and launch them on a safe passage to prosperity."

Annan was sharply critical, however, of the NATO-led air war against Yugoslavia, which was mounted without the approval of the U.N. Security Council. Fearing a veto from Russia or China, the United States and its European allies decided to circumvent the Security Council, which is nominally the global institution empowered to authorize war.

"The inability of the international community in the case of Kosovo to reconcile . . . universal legitimacy and effectiveness in defense of human rights can only be viewed as a tragedy," Annan said.

Annan's address was followed by speeches from presidents, prime ministers and foreign ministers from 20 governments, including Brazil, South Africa, Algeria, Namibia and France. President Clinton, who traditionally delivers his speech on opening day, postponed his appearance in deference to the Yom Kippur holiday, and will speak Tuesday.

Annan's call for greater U.N. involvement in peacekeeping operations represents something of a change of course for the United Nations, which has been scaling back its overseas responsibilities over the past five years. In 1994, the United Nations had more than 75,000 troops deployed in peacekeeping operations around the world at a cost of $3.6 billion. This year, with the withdrawal of a U.N. peacekeeping mission in Angola, the U.N. foreign peacekeeping force has fallen to about 12,000, at a cost of $870 million.

Annan is asking for international support to mount peacekeeping missions to help end three African conflicts--in the Congo, Sierra Leone and on the border between Ethiopia and Eritrea. But he said the reach of international organizations is entering into every aspect of world affairs, from the creation of global trade rules at the World Trade Organization to the far-flung reach of the Internet.

"State sovereignty, in its most basic sense, is being redefined by the forces of globalization and international cooperation," Annan said.

The speech was received warmly by many countries, reflecting broad international support for a more activist United Nations. In fact, some governments said the United Nations should be doing more, particularly in Africa. "The United Nations must strive to respond to crises wherever they occur," said France's Prime Minister Lionel Jospin. "While we have not hesitated to do precisely that over the past few years and on several continents, I would like to express regret of the relative timidity of the organization whenever Africa is concerned."

South African President Thabo Mbeki, in his first U.N. address as South Africa's head of state, echoed those concerns, adding that the United Nations needs "to act with all necessary vigor" to end African conflicts. But he also criticized the monopoly on power in international affairs held by a small group of nations, most notably the United States.

The tone of the opening session was less hostile toward the United States than in previous years, when Washington came under fire for failing to pay its back dues to the United Nations.

The United Nations contends that Washington owes more than $1.6 billion and could lose its vote in the U.N. General Assembly in January if it fails to pay at least $350 million before Dec. 31.

CAPTION: U.N. Secretary General Kofi Annan criticized NATO for waging