United Nations ? Under heavy security, the U.N. General Assembly convened its 57th annual session on Tuesday, preparing for two weeks of debate over the prospect of war or peace for Iraq.

In the anniversary week of the Sept. 11 attacks, the United Nations also will focus on the struggle against terrorism. The incoming General Assembly president, Czech Foreign Minister Jan Kavan, listed it first among the U.N. priorities for 2002-2003, calling for early completion of a comprehensive treaty against terrorism that is under negotiation here.

Swiss President Kaspar Villiger, center, speaks to an audience outside U.N. headquarters in New York, where the Swiss flag took its place among other member nation flags. Switzerland was admitted to the U.N. Tuesday during the first meeting of the 57th General Assembly. U.N. Secretary-General Kofi Annan stands at left. Others in the photo are unidentified.

Ambassadors, foreign ministers, presidents and premiers from the nations of the world were converging on the United Nations’ New York complex this week under some of the heaviest security ever seen here.

Helicopters swept through the skies, U.S. Coast Guard and police boats patrolled the nearby East River, and police barricades blocked the immediate area on Manhattan’s East Side, just a few miles from the former site of the World Trade Center towers.

Security will be toughest on Thursday, when President Bush addresses the General Assembly and lays out the U.S. case for considering military action to oust the government of Iraq’s President Saddam Hussein.

Bush’s speech will be the second among more than 180 over eight days by heads of state and other national representatives. Others also are expected to address the issue of what, if anything, should be done regarding Iraq, accused by the Bush administration of developing weapons of mass destruction and planning to use them.

One of the General Assembly’s first pieces of business Tuesday was the admission of Switzerland, which for 56 years had chosen to remain outside the world body, rather than risk compromising its neutrality by entanglement in U.N. bloc politics.

The new assembly president Kavan, a former Czech anti-communist dissident, listed as other priorities:

Conflict prevention, “to move from a culture of reaction to a culture of prevention.”

Work toward eradication of extreme poverty, which can lead to a feeling of “powerlessness, frustration and anger.”

A “more representative Security Council,” a goal of Japan, India and others that want to update the most powerful United Nations body, whose structure was set decades ago.

President Bush to challenge U.N. on Iraq.