The US Congress is stepping up its efforts to clamp down on Iran to deter it from acquiring nuclear weapons.
A group of 249 bipartisan lawmakers sent a letter to President Joe Biden, demanding he take additional steps to address Iran's nuclear program and prepare to reimpose UN sanctions on Tehran.
The letter, put forward by Republican Dan Crenshaw and Democrat Abigail Spanberger, said the US "must increase its efforts to prevent Iran from obtaining nuclear weapons, and to communicate to Iran, without any ambiguity, that any further progress in its nuclear program will result in severe consequences."
It also cites Iran's "strengthened alliance" with Russia and China, which bolsters the "Iranian regime's confidence and may make them more likely to challenge US allies and interests."
The letter bore the signatures of 110 Democratic representatives, including representatives who supported the efforts of former President Barack Obama's administration to conclude the nuclear agreement with Tehran.
It is not the first time lawmakers have addressed such a letter to the White House.
Last week, senators sent a similar letter urging the Biden administration to work with European allies to prepare to reinstate sanctions on Iran if it raises its rate of uranium enrichment to 90 percent.
A bipartisan group of 26 senators wrote that the "Congress stands united behind the long-held bipartisan position that Iran must never be allowed to obtain a nuclear weapon."
"It is crucial for your administration to remain aligned with Congressional efforts related to Iran's nuclear program and not agree to a pact that fails to achieve our nation's critical interests. We urge you to take meaningful steps to curb Iran's destabilizing activities and deter the regime from pursuing this nefarious ambition any further."
The letters coincide with bills put forward by lawmakers from both parties in the Senate and House of Representatives to restrict the administration's movement in the negotiations with Iran.
The latest of these bills was submitted by top Republican on the Senate Foreign Relations Committee, Senator Jim Risch, reminding the White House of the legal necessity to return to Congress upon reaching any agreement with Tehran.
"As the Biden Administration contemplates another enormous cash windfall to the Iranian regime in exchange for dubious non-proliferation promises, it is vitally important that Congress has a voice in any sanctions relief," said Risch.
"Iran remains actively engaged in supporting Russia's unprovoked war in Ukraine and continues to attack our troops and diplomats. [...] Congress has an obligation to ensure that sanctions relief does not fund these appalling activities."