BRUSSELS - Iran would improve its chances of playing a role on the sidelines of Syria peace talks this month by working with Damascus to end its bombardment of civilians and to improve access for humanitarian groups, US officials said on Monday.The officials, who spoke on condition of anonymity, said such actions, in public or in private, would make other countries more likely to include Iran in a Jan. 22 peace conference that seeks to end the Syrian civil war.One official told reporters traveling with US Secretary of State John Kerry that Washington believed it was still "less likely than likely there will be any role" for Iran at the talks, to be held on Lake Geneva in Switzerland."There are ... steps that Iran could take to show the international community that they are serious about playing a positive role. Those include calling for an end to the bombardment by the Syrian regime of their own people ... and encouraging humanitarian access," said one of the officials.A second official said that the United States would be satisfied if Tehran were to work quietly with Damascus to achieve those two goals rather than doing so publicly."Public or private, we'd take it either way at this point," the second official said.Kerry on Sunday reiterated US opposition to Iran being a formal member of the so-called "Geneva 2" talks because it does not support the 2012 international agreement on Syria, dubbed "Geneva 1". But he said there might be ways that Iran could "contribute from the sidelines".