Iran sanctions renewal becomes law without Obama's signature
US president Barack Obama has unexpectedly declined to sign legislation renewing sanctions against Iran - but has let it become law anyway.
Mr Obama faced a midnight deadline to sign the 10-year renewal of the decades-old sanctions law and the White House said he was expected to sign it.
But White House press secretary Josh Earnest said on Thursday Mr Obama was letting it become law without his signature, saying he retained authority to waive all nuclear sanctions lifted as part of the deal reached with Tehran.
Iran's president had vowed to respond if the sanctions were renewed, arguing that they violate terms of the nuclear deal. The White House disagreed but said Mr Obama would sign it begrudgingly, despite deeming it unnecessary.
President-elect Donald Trump has been sharply critical of the nuclear deal.
Under the US Constitution, the president has 10 days after Congress passes a bill to sign it, veto it or let it become law with no signature if Congress is still in session.
Although members have returned home for Christmas, Congress technically has not adjourned and is holding "pro-forma" sessions this week.
Though Mr Obama's move does not prevent the sanctions renewal from entering force, it marked a symbolic attempt by the president to demonstrate disapproval for politicians' actions.
The White House has argued that the renewal is unnecessary because the administration retains other authorities to punish Iran if necessary, and has expressed concern that the renewal may undermine the nuclear deal.
Iran's government has complained to the United Nations about the renewal and on Tuesday, the president ordered up plans to build nuclear-powered ships and to formally accuse the US of breaking the terms of the deal.
Yet US politicians argued that renewing the law, first passed in 1996 and renewed several times since, was critical to maintaining pressure on Iran to abide by the deal and to pushing back on Tehran's other troubling behaviour in the region. The bill passed the Senate unanimously and the House of Representatives by an overwhelming margin.
The Obama administration stressed that Iran would be unaffected by the renewal as long as it continues honouring the nuclear deal. Secretary of state John Kerry said he told his Iranian counterpart that "to ensure maximum clarity" he had issued new, redundant waivers exempting Iran from sanctions lifted under the deal.
"Extension of the Iran Sanctions Act does not affect in any way the scope of the sanctions relief Iran is receiving under the deal or the ability of companies to do business in Iran consistent with the JCPOA," Mr Kerry said, using an acronym for the deal.
Mr Trump has threatened to try to renegotiate the deal and Israel's prime minister has said he plans to lobby Mr Trump to undo it.
Republican supporters of the sanctions had argued that renewing them would ensure that Mr Trump would have the authority to reinstate penalties that Mr Obama eased.
Under the nuclear deal, the US and world powers suspended sweeping oil, trade and other financial sanctions that had devastated Iran's economy.
In return Tehran agreed to roll back its nuclear programme, though the deal's critics say the agreement is flawed because it did not halt all Iranian activity, and key restrictions eventually expire.