Forty-nine of the 50 Republican US senators said on Monday they will not back an emerging new nuclear deal between Iran and world powers, underscoring their party"s opposition to attempts to revive a 2015 accord amid fears talks might collapse. Citing press reports about the as-yet-unfinalized agreement, which could be torpedoed by Russian opposition, the lawmakers said in a statement that Democratic President Joe Biden"s administration might reach a deal to weaken sanctions and lessen restrictions on Iran"s nuclear program. They pledged to do everything in their power to reverse an agreement that does not "completely block" Iran"s ability to develop a nuclear weapon, constrain its ballistic missile program and "confront Iran"s support for terrorism." No congressional Republicans supported the 2015 nuclear agreement between Tehran and major powers, reached under Democratic President Barack Obama, that curbed Iran"s uranium enrichment program in exchange for a lifting of international sanctions against Tehran. A handful of Democrats also objected. Congress may have the right to renew an agreement under the 2015 Iran Nuclear Agreement Review Act (INARA), but lawmakers are unlikely to be able to kill a deal outright after failing to do in 2015 when Republicans controlled Congress. Democrats, who now hold slim majorities in both the House of Representatives and Senate, are unlikely to turn against Biden in sufficient numbers to stop a major initiative like an Iran deal. The 2015 accord made it harder for Tehran to develop material for nuclear weapons. It fell apart after Republican President Donald Trump withdrew the United States in 2018, saying it was flawed to Iran"s advantage. Talks resumed after Biden became president last year. Attempts to clinch a new deal were left in limbo after a last-minute demand by Russia - at odds with the West over its invasion of Ukraine - forced the powers to pause talks in Vienna despite having a largely completed text. — Agencies