The Biden administration’s efforts to re-engage with Iran over its nuclear program are coming up against three major obstacles: a lack of direct channels of communication, divisions within the leadership in Tehran, and looming Iranian presidential elections, U.S. officials involved in the talks tell me.Why it matters: Putting Iran’s nuclear program “back in the box” is one of the Biden administration’s top foreign policy priorities, but the sides have yet to hold direct talks.Get market news worthy of your time with Axios Markets. Subscribe for free.President Biden says he’s willing to lift sanctions and return to the 2015 nuclear deal if Iran returns to full compliance, by rolling back the nuclear acceleration it has undertaken since Donald Trump withdrew from the deal in 2018. Behind the scenes: The Iranians have rejected several U.S. proposals to meet formally or even informally.The U.S. officials tell me all of their communications with Tehran are coming indirectly, through the E3 (France, the U.K. and Germany), Russia, China or the EU.This takes more time and has led to several misunderstandings, the U.S. officials say.In recent weeks, the U.S. has sent messages to Iran that it is ready to either start with mutual first steps and follow a gradual process from there, or for both sides to immediately return to full compliance with the deal, the U.S. officials tell me.Through the indirect channels, the U.S. has been trying to gauge what it will take to get the talks going. At one point, the U.S. believed the Iranians were ready to accept a step-by-step approach. Then the Iranians made clear that they were not.The U.S. had proposed that the process begin with the U.S. unfreezing Iranian funds held in South Korea, and Iran taking steps to end some of its violations of the deal, according to U.S. and Israeli sources briefed on the matter. The Iranians rejected that proposal.Between the lines: The Biden administration is struggling to understand how exactly the Iranians want to proceed, and thinks the lack of clarity is due in part to divisions within the Iranian leadership, U.S. officials say.One key debate seems to be over whether to engage with the U.S. before or after the elections in June.What to watch: Politico reported on Monday that the U.S. is developing a new proposal for Iran in an attempt to get the talks started.But an Iranian official told state TV that Iran won’t scale back its nuclear activities before the U.S. removes all sanctions imposed by the Trump administration.”The Biden administration is losing time. If it fails to lift the sanctions soon, Iran will take the next steps, which will be further reduction of its JCPOA commitments,” the Iranian official added. Where things stand: The U.S. is discussing new ideas internally and with the other parties to the nuclear deal, but no consensus has been reached, one U.S. official told me.“The process will take more time because the discussions between the U.S. and Iran are indirect,” the official said.Like this article? Get more from Axios and subscribe to Axios Markets for free.