The United Nations has approved a treaty aimed at preventing nuclear terrorism.Passageof the measure ends seven years of negotiations.

In the end, no vote was necessary. The 191-member General Assembly adopted the "International Convention for the Suppression of Acts of Nuclear Terrorism" by consensus.

But the road to approval was long, and at times uncertain. The measure was introduced by Russia in 1998 at a time when Moscow was concerned that Cold War-era weapons might fall into the hands of terrorists.

It had remained stuck in the General Assembly's legal committee for years,bogged downby what are known as "killer amendments" introduced by the United States, Pakistan, Cuba and Iran. The U.S. proposal was aimed at preventing states from using peaceful nuclear programs as a cover for weapons development.

But all four amendments were withdrawn after President Bush and Russian President Vladimir Putin urged passage of the measure at their February meeting in Bratislava.

The measure is the 13th U.N. anti-terrorism convention, and the first adopted since the September 11, 2001 terror attacks on the United States.

Addressing the General Assembly, Washington's deputy U.N. ambassador Stuart Holliday said the unanimous approval shows that the world body, when it has the political will, can play an important role in the global fight against terrorism.

"We are pleased that Member States demonstrated a seriousness of purpose and worked together in this multilateral setting to conclude the Convention and thereby send an undeniably clear signal that the international community will not tolerate those who threaten or commit terrorist acts involving radioactive material or nuclear devices," he said.

Ambassador Holliday called for other countries to build on the nuclear terrorism treaty by agreeing on a Comprehensive Convention on International Terrorism, which remains stalled.

The treaty adopted Wednesday obligates governments to prosecute or extradite anyone who possesses or threatens to use radioactive materials with intent to cause death or injury.

The accord is to be opened for signatures on September 14, during a summit of world leaders in New York. It needs ratification of 22 countries to become international law.