Iran has given an updated proposal for a deal to end the war, but the White House believes it is not a meaningful improvement and is insufficient for a deal, a senior U.S. official and a source briefed on the issue told Axios. Why it matters: U.S. officials say President Trump wants a deal to end the war, but is considering resuming it due to Iran's rejection of many of his demands and refusal to make meaningful concessions on its nuclear program.Trump is expected to convene his top national security team in the Situation Room on Tuesday to discuss military options, two U.S. officials said.The senior U.S. official said that if Iran won't shift its position, the U.S. will have to continue the negotiations "through bombs."Trump told Axios in a phone call on Sunday, before the U.S. had received Iran's later offer, that "the clock is ticking" and if Iran doesn't show flexibility, "they are going to get hit much harder."Zoom in: The senior U.S. official said the Iranian counter-proposal, which was shared with the U.S. on Sunday night via the Pakistani mediators, has only token improvements on the last version.The new proposal includes more words on Iran's commitment not to pursue a nuclear weapon, but no detailed commitments about suspending uranium enrichment or handing over its existing stockpile of highly enriched uranium.While Iranian state media reported that the U.S. had agreed to waive some oil sanctions on Iran during the negotiations, the U.S. official said no sanctions relief will happen "for free" without reciprocal action by Iran.What they're saying: "We are really not making a lot of progress. We are at a very serious place today. The pressure is on them to be responsive in the right way," the senior U.S. official said. "It's time for the Iranians to throw bit of candy out. We need some real, sturdy, and granular conversation [regarding the nuclear program]. If that's not gonna happen, we will have a conversation through bombs, which will be a shame."Between the lines: The senior U.S. official said the U.S. and Iran aren't having direct negotiations on the substance of the agreement, but are engaged in indirect talks to try and develop consensus around what these negotiations will look like.The U.S. official claimed the fact that Iran made a new counter-offer, despite the very modest changes, suggests the Iranians are concerned about further U.S. military action.The Iranians have long claimed it is Trump who is desperate for a deal, and that time is on their side.State of play: Pakistani Interior Minister Mohsin Naqvi, spent three days in Tehran as part of the mediation efforts and returned to Islamabad on Monday.Turkish Foreign Minister Hakan Fidan, who is also involved in the mediation, said at a press conference in Berlin on Monday that he hopes the U.S. and Iran "are aware of dangers of restarting the war."He said Qatar, Egypt and Saudi Arabia are also participating in the mediation efforts and stressed both the U.S. and Iran need to find middle ground and agree to end the war.Go deeper: Trump's killer quote exposes his bind on Iran and inflation