A U.N. conference on nuclear nonproliferation due to take place in New York from early next month was postponed again because of surging COVID-19 cases, diplomatic sources said Wednesday.

The meeting to review the Treaty on the Non-Proliferation of Nuclear Weapons was scheduled to be held Jan. 4 to 28 in New York after being delayed three times from its original date in 2020 due to the coronavirus pandemic.

The NPT, joined by 191 countries, is the world's most widely ratified nuclear arms control agreement. Its review conferences involving both nuclear and non-nuclear states have been held every five years since 1975, with the last gathering in 2015.

The third and final session of the Preparatory Committee for the 2020 Nuclear Non-Proliferation Treaty review conference begins in New York, on April 29, 2019. (Kyodo) ==Kyodo

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U.N. nonproliferation talks to be postponed again due to pandemic

Following the postponement, the sources said speeches by signatory representatives may be held online by the end of January and in-person discussions organized later. But the schedule is still fluid.

The United States and some European countries have seen a sharp rise in COVID-19 cases with the emergence of the Omicron variant, prompting authorities to bring back some restrictions at indoor venues and on public transportation.

New York is among the hardest-hit areas in another wave of infections in the United States and the administration of President Joe Biden is scrambling to get more people vaccinated and provide booster shots.

A U.N.-adopted Treaty on the Prohibition of Nuclear Weapons, which entered into force in January this year, is more ambitious in its approach to eliminating nuclear weapons, but its effectiveness is in question as it lacks support from nuclear weapon states such as the United States, Russia and China.